A few modest changes to the wizard and archivest classes.

[Agrippa]

Most people want to eliminate spell preparation claiming that it was a stupid idea in the first place. Not me of course. I just modify it heavily. Instead of spells per day I intend to use "spells prepared". A wizard or archivest may have upward's of seven spells, plus additional slots from feats, partially cast at any one time to be triggered. All spells are retained until cast and a new spell may be prepared in its place. However a single spell can be prepared only once at a time. That said any non-buffing and non-skill duplicating spell with a level equal to one third of the wizard's/archivest's level can be cast three times before being spent.

{table=head]Level|Maximum spell level|Spells prepared
1st|1|3
2nd|1|3
3rd|2|3
4th|2|4
5th|3|4
6th|3|4
7th|4|4
8th|4|4
9th|5|4
10th|5|5
11th|6|5
12th|6|5
13th|7|5
14th|7|5
15th|8|6
16th|8|6
17th|9|6
18th|9|6
19th|9|6
20th|9|7
[/table]

On preparing spells.

In the works of Jack Vance and Roger Zellzany spells wizards could cast could take up to a half-hour or full hour to cast due to the complex mathematical and scientific formulas required. This rendered them mostly useless in combat if it weren't for memorization. Basically in this system of spell casting if you wanted to memorize a spell that would take ten minutes to cast spontaneously you would spend nine minutes to nine minutes and 48 seconds pre-casting 90% to 98% of the spell in your head. The two round to one minute casting time (reserved for highly powerful/complex spells) would only be a fraction of the real casting time thus setting off the spell.

{table=head]Level|Preparation time|Casting time
0|

30 seconds

|free action
1st-2nd|

1 minute

|standard action
3rd-4th|

5 minutes

|one round, five rounds for non combat spells*
5th-7th|

10 minutes

|two rounds, 1 minute for non combat spells
8th|

30 minutes

|four rounds, 2 minutes for non combat spells
9th|

one hour

|six rounds, 3 minutes for non combat spells
[/table]

Now I do plan to use a different spell slot method for wizards though which I'll post in a few hours.

*Spells like gate, clone, the wish line and animate dead. Of course durations for certain spells would have to be lengthened too.

[Chambers]

I really liked the way Zelazny handled magic in the Merlin part of the Amber stories. If you wanted to model D&D magic on that I have a few suggestions.

• Each class has a power source. This is mainly flavor note and doesn't have any game effect, as each class already has a distinct source of spells.
• Spells are hard to maintain and decay over time without use.
• Spells have most of their casting done in the creating of the spell and only require a few quick gestures to complete and actually cast the spell.
• Casters may use raw magical energy to blast instead of casting spells, but this is harmful to them.

You've already got some of these elements, but I'd change the specifics of your casting mechanic. As I noted in the other thread the casting times are too long. It's problematic from a game mechanic standpoint, but it's also not how magic is prepared in the books. In the last book... (Spoiler!)

Spoiler

Show

Merlin is slinging spells left and right, dueling with his mom and uncle. He's countering multiple spells a round and casting multiple spells a round, all high level. Granted, the spells he casts are provided by the ring but he's able to cast them instantly.

I think a D&D game based on the casting of Amber would be really cool, but I think you'd have to change some basic assumptions about how all magic in the game works, not just wizards and other prepared casters. If a Sorcerer can drop spells as a standard action but the Wizard takes multiple rounds, it's no contest.

[Agrippa]

First only prepared casters use this casting system. In fact sorcerers can't cast wizard spells and visa versa. Basically the sorcerer would be a reskinned psion. And a whole lot else related to psionics would be reflavored as sorcerery. That's all I can think of tonight.

[Milskidasith]

First only prepared casters use this casting system. In fact sorcerers can't cast wizard spells and visa versa. Basically the sorcerer would be a reskinned psion. And a whole lot else related to psionics would be reflavored as sorcerery. That's all I can think of tonight.

That makes Sorcerers amazing, and higher level wizards pretty bad. Except, of course, for the fact you can force a crapload of saves against daze every round with cantrips, which I assume wasn't your intention. If only there was a way to get more cantrips...

[Chambers]

That makes Sorcerers amazing, and higher level wizards pretty bad. Except, of course, for the fact you can force a crapload of saves against daze every round with cantrips, which I assume wasn't your intention. If only there was a way to get more cantrips...

Lol. I think there's a Cantrip only homebrew casting class around here somewhere.

[Stompy]

I've seen a similar take on the system. The same question remains, what happens to metamagic? (In theory, a quickened black tenticles takes either longer, shorter, or maybe even the same time.)

[Agrippa]

For psions sorcerers spells take an amount of time to cast equal the standard casting time plus standard casting time x be half then umber of augmentation points. Move actions are treated as two standard actions while full-round actions are treated as three standard actions. That means that a power spell with a standard action casting time augmented by 12 points would take four-full round actions plus one standard action to cast. They'd also require somatic and or verbal components just like wizardry as well as differing displays.

....
As for meta-magic feats try these revisons on for size.

Quicken Spell [Metamagic]
Prerequisite
Wizard spellcasting at caster level 10th or higher.

Benefit
The creature can quicken three spells per day.

Using a quickened spell is a free action that does not provoke an attack of opportunity. The wizard can perform another action—including the use of another spell—in the same round that he or she uses a quickened spell. The wizard may use only one quickened spell per round.

The wizard can only apply this feat to a spell with a level less than or equal to half his or her caster level (round down) -4. For a summary, see the associated table.

In addition, a spell with a casting time greater than 1 full round cannot be quickened.

Normal
Normally the use of a spell requires a standard action and provokes an attack of opportunity unless noted otherwise.

Special
This feat can be taken multiple times. Each time it is taken, the creature adds another three to number of times they may quicken a spell in any one day.

Quicken Spell
{table=head]Spell Level||Caster Level to Quicken
0|8th
1st|10th
2nd|12th
3rd|14th
4th|16th
5th|18th
6th|20th
7th|22nd
8th|24th
9th|26th
10th|28th
11th|30th
12th|32nd
13th|34th
14th|36th
15th|38th
16th|40th
17th|42nd
18th|44th[/table]

Empower Spell [Metamagic]
Prerequisite
Wizard spellcasting at caster level 6th or higher.

Benefit
The wizard can empower three spells per day.

When a wizard uses an empowered spell, all variable, numeric effects of the spell are increased by one half. Saving throws and opposed rolls are not affected. Spell abilities without random variables are not affected.

The wizard can only select a spell with a level less than or equal to half its caster level (round down) -2. For a summary, see the table in the description of the Empower Spell feat.

Special
This feat can be taken multiple times. Each time it is taken, the wizard adds another three to number of times they may empower a spell in any one day.

Empower Spell
{table=head]Spell Level||Caster Level to Empower
0|4th
1st|6th
2nd|8th
3rd|10th
4th|12th
5th|14th
6th|16th
7th|18th
8th|20th
9th|22nd
10th|24th
11th|26th
12th|28th
13th|30th
14th|32nd
15th|34th
16th|36th
17th|38th
18th|40th[/table]


Enlarge Spell [Metamagic]
Prerequisite
Wizard spellcasting at caster level 4th or higher.

Benefit
The wizard can enlarge three spells per day.

You can alter a spell with a range of close, medium, or long to increase its range by 100%. An enlarged spell with a range of close now has a range of 50 ft. + 5 ft./level, while medium-range spells have a range of 200 ft. + 20 ft./level and long-range spells have a range of 800 ft. + 80 ft./level.

The wizard can only select a spell ability duplicating a spell with a level less than or equal to half its caster level (round down) -1. For a summary, see the table in the description of the Enlarge Spell feat.

Special
This feat can be taken multiple times. Each time it is taken, the wizard adds another three to number of times they may enlarge a spell in any one day.

Enlarge Spell
{table=head]Spell Level||Caster Level to Enlarge
0|2nd
1st|4th
2nd|6th
3rd|8th
4th|10th
5th|12th
6th|14th
7th|16th
8th|18th
9th|20th
10th|22nd
11th|24th
12th|26th
13th|28th
14th|30th
15th|32nd
16th|34th
17th|36th
18th|38th[/table]


Extend Spell [Metamagic]
Prerequisite
Wizard spellcasting at caster level 4th or higher.

Benefit
The wizard can extend three spells per day.

An extended spell lasts twice as long as normal. A spell with a duration of concentration, instantaneous, or permanent is not affected by this feat.

The wizard can only select a spell with a level less than or equal to half its caster level (round down) -1. For a summary, see the table in the description of the Extend Spell feat.

Special
This feat can be taken multiple times. Each time it is taken, the wizard adds another three to number of times they may extend a spell in any one day.

Extend Spell
{table=head]Spell Level||Caster Level to Extend
0|2nd
1st|4th
2nd|6th
3rd|8th
4th|10th
5th|12th
6th|14th
7th|16th
8th|18th
9th|20th
10th|22nd
11th|24th
12th|26th
13th|28th
14th|30th
15th|32nd
16th|34th
17th|36th
18th|38th[/table]


Maximize Spell [Metamagic]
Prerequisite
Wizard spellcasting at caster level 8th or higher.

Benefit
The wizard can maximize three spells per day.

All variable, numeric effects of a spell modified by this feat are maximized. Saving throws and opposed rolls are not affected, nor are spells without random variables.

An empowered, maximized spell gains the separate benefits of each feat: the maximum result plus one-half the normally rolled result.

The wizard can only select a spell with a level less than or equal to half its caster level (round down) -3. For a summary, see the table in the description of the Maximize Spell feat.

Special
This feat can be taken multiple times. Each time it is taken, the wizard adds another three to number of times they may maximize a spell in any one day.

Maximize Spell
{table=head]Spell Level||Caster Level to Maximize
0|6th
1st|8th
2nd|10th
3rd|12th
4th|14th
5th|16th
6th|18th
7th|20th
8th|22nd
9th|24th
10th|26th
11th|28th
12th|30th
13th|32nd
14th|34th
15th|36th
16th|38th
17th|40th
18th|42nd[/table]

How does this work?

[Chambers]

How does this work?

It still doesn't address this point:

That 9th level spell takes 6 rounds to cast. That's six rounds that the Wizard can get attacked and has to make concentration checks to maintain the spell. At levels where Wizards are casting 9th level spells it's not unreasonable to be dealing out 100pts of damage, possibly per attack. The Wizard isn't going to 1) Survive long enough to cast the spell and 2) Make the Concentration check DC of 10 + the damage taken to actually cast the spell once the six rounds have passed.

I really like the idea of Zelazny type magic...but I think the mechanics you're implementing hurt casting to the point where it's not able to perform effectively.