Quote Originally Posted by Ignimortis View Post
Because it doesn't matter 90% of the time if your solution is 10/10 or 6/10 - what matters is whether you can do it at all.
Then how is Teleport better than Shadow Walk? If it is in fact true that these things are binary yes/no checks, then the Beguiler isn't actually substantively less versatile than the Wizard for having the latter rather than the former.

Moreover, even if it is true that challenges are all binary yes/no switches, that still doesn't mean you can't make meaningful choices between abilities. If all you need is a hammer, it still matters if you can use that hammer at-will (Warlock) or learn that hammer for free (Warmage).

Well, make it a ritual, at least. Fabricate is certainly not a thing that should be on spell lists and cast with a single level 5 slot in a few minutes.
Why not? The balance of Fabricate really isn't particularly effected by how long it takes to cast as by how many times per day you can do it. I can certainly imagine that you might want to make spell slots in general an encounter-level resource, at which point Fabricate would need to have some other balancing mechanism, but that could very easily be a pool of daily charges, or costing some kind of mana gems.

If you want to rely on the Rogue for stealth, they have to be better at stealth than Invisibility starting at level 3.
No, they don't. They have to be good enough at stealth that the resources they save from not requiring you to use a 2nd level spell slot on Invisibility are worth more than the resources you'd save from more efficient stealth. You have an oversimplified model of costs, and it is causing you to blithely assert that problems that are actually quite easy to deal with must be insoluble.

Of course, we also need to make sure that it's not something that's best solved with "the Wizard can teleport us there, and then charm the king into believing us, and scry on the cultists, and then set up wards". Because that would be the current situation
Except no it wouldn't, because the Beguiler is better at charming the king, and the Cleric is (depending what you mean) better at setting up wards. So all we actually need to do is write a Fighter class with meaningful scrying or teleporting and we're done.

Bugbears are by default not equipped to deal with Fireballs, since Fireball is a level 5 thing. Compare a Bugbear to Magic Missile or Scorching Ray - they also won't die from one of those. Monster HP doesn't scale linearly with CR - HD gain is way faster that CR gain.
If you go back to the original point I made, I was using the Bugbear as an example of a monster you'd encounter in a group at 5th level, and comparing it to a monster you'd encounter in a group at 10th level to see how Fireball scales over that period. The CR 2 Bugbear is the same relative CR as the CR 7 Hill Giant, but has way less HP relative to an equal-level Fireball. Which means that Fireball is not keeping up at 10th level.

Having solutions to problems that couldn't really be handled without them. Or making it way easier to handle problems the party did encounter.
You're still not really defining things in a way that's usable for relative measurement. The question isn't if a 8th level Wizard can do some stuff we think is cool. The question is if the stuff that Wizard can do is more useful than what a 10th or 11th level Dread Necromancer can do. You've got to think in terms of opportunity cost, and to acknowledge not just the points where the character might be better ("we need exactly Dimension Door for some reason") but also the points where they are worse ("it turns out having 5th level spells is pretty cool").