Ki Spellcasting: Domain Monks and Bloodline Ninjas (help)

[Bucky]

I think the fluff of the Ki classes lends itself well to very restricted spellcasting; Monks get their powress from their doctrine and adherence to a philosophy, while Ninjas have secret techniques up their sleeves. Also, Ki manipulation is itself magical.

Also, both classes could use more flexible options during character building.

What I want to do is give them casting off a very small spell list: Monks choose a single domain and can cast spells from that domain, while Ninjas choose a sorcerer bloodline and can cast the bonus spells known from that bloodline.

I also want to follow the conventions for archetypes - a class feature must be traded away for each class feature gained, and an archetype as a whole shouldn't be too far out of balance with the base class.

So, the basics:
* Domain Monks and Bloodline Ninjas trade away either their Ki pool or all the default uses of it and gain the ability to cast spells. I need help figuring out how this should work.
* Domain Monks trade Stunning Fist for the domain powers. I don't know what to do about the Stunning Fist modes gained at level 12, 16 and 20.
* Bloodline Ninjas trade a fixed Class Skill (Bluff or Intimidate?) for their Bloodline Skill.
* Bloodline Ninjas trade their tricks at 6, 12 and 18 for bloodline feats. They can also take up to 2 of their bloodline feats as ninja tricks but can't take other tricks that grant bonus feats.
* Bloodline Ninjas trade (something?) for bloodline powers.


Leaving the questions:
0) Is this worth fleshing out? Would it be used outside my campaign?
1) How should spellcasting work? Should they get spell slots, or spend Ki as PP, or both?
2) What class skill should Bloodline Ninjas lose for their Bloodline skill?
3) What should Bloodline Ninjas lose in exchange for bloodline powers?
4) Should Domain Monks gain anything in exchange for their advanced Stunning Fist variants?

[Lichtenstein]

perhaps:
break them into 3 groups
1-3rd level spells - 1 ki point to use
4-6th level spells - 2 ki points
7-9th level spells - 3 ki points to use

with each spell becoming available at every other level. This might replace gained ki powers, there are 9 starting at 4th level, gained every other level so that works out. Domain powers are at 1st and some other level. The first domain power can replace stunning fist. If the second power is granted at level 7 or below, it replaces the bonus feat gained at 6th level. If the second power is granted at level 8 or above, it replaces the bonus feat gained at 10th level.
Or maybe the extra stunning fist stuff is valuable enough to not lose a feat at all. Not really sure, since the stunning fist stuff is really nice but its dc to resist is low

Sorcerers get bloodline stuff every odd level and at 20th. Since the magic and feats they get can help them in combat, it seems ok to entirely replace their sneak attack with these abilities, and to grant their ki pool at 1st level to replace their first sneak attack. They gain their first bloodline spell at 3rd level and every 2 after that until 19th, so that works out nice for 9 spells. At 20th level Hidden Master or Ninja Trick should be replaced. It seems a shame to give up Hidden Master since its a core idea of a ninja, but it does compete for ki point resources with the spell list, so it's actually a little less powerful in this variant of ninja, and shall not be as missed.

This makes ninjas slightly more powerful spellcasters than monks, but that seems ok, since the unchained monk has much more combat ability than a ninja without sneak attack.

Monks and ninjas gain a caster level equal to their level. Monks gain this at 4th level, ninjas gain it at 1st level.

Probably also want to increase their ki points to 1 point / level + relevant modifiers instead of 1/2 level + modifier

[Bucky]

I'm thinking:
*Bloodline stuff replaces all Ninja tricks. Ninjas get some abilities one level late and some one level early, doubling up in one case to compensate for the extra ability at 20.
*Monks get domain spell slots, spend Ki at a rate of 1 per spell level to recover spent spells, and get extra Ki from their high level stunning fists.
*Ninjas spend Ki for spells at a discount relative to Monks, but don't get domain slots.
*Ninjas keep Sneak Attack; otherwise they wouldn't be ninjas.

[Deepbluediver]

I've got my own ideas about Monks, but I've I've considered both the Assassin spell-list and some variant of Shadow Magic (from The Tome of Magic) for the Ninja. If you want inspiration, those might be good places to look.

[Sicarius Victis]

For the Ninja, I'd say just letting them learn slightly modified spells as ninja tricks, similarly to Vanishing Trick.