[SolAndLuna]

One thing I'll note is for this:

I'll stick to wanting to keep three turn cooldowns for spells. If it were two, then if I go last then it's effectively 1 turn of a cooldown depending on how it works. So.You get enough potency out of the spells for minimal SP Investment and all that. Stolen Spells should keep their cooldown for now. Any cooldown reduction on that would make you opt to not have to think as much.

It doesn't actually matter whether you're first or last in this case, I don't think? Just means that you can't spam a spell, and that you can't use it next turn regardless of whether you were first or not. Your turn ends and the counter progresses at the same time everyone else's does, after all, the only case where that changes is if someone finds a way to double turn someone else, unless I'm missing something.

Past that, the ideas you offered sound interesting, to be honest? I definitely wouldn't have too many issues with that as long as I still get to keep enough copy spells inbetween fights, and it sounds like it'd be really interesting to be able to combine spells in some way. There are a few reasons I didn't offer those kinds of more detailed solutions, though.

First one is simply that it takes a lot of time and effort to implement, and I'd imagine there are other overall less effective/interesting classes that need a rework way before Spellthief does. Second is that... well, any large change to things runs the risk of existing builds suddenly losing effectiveness and needing to have their skills/classes changed, which is never fun, and having it happen to a class that's already relatively weak in some aspects would probably make some people fairly sour. Third, and likely most important, is that I'm afraid it could go down the same road things like Ghost did - unintentionally powered up by far more than initially expected, people complain about it being overpowered, and eventually it gets nerfed again and again.

Granted, these are concerns that can be addressed, if something like this ends up happening - updates can simply come in an order of most to least important, and a quick look over what Spellthief is currently used for should resolve any issues with new setups invalidating old ones entirely. As for the possibility of overbuffing the class, that could likely be checked with either a test server or just letting people talk about the balance for the proposed changes, potentially.

So, all in all, I wouldn't mind this sort of solution, either, but I figured that looking at the simplest solutions should be done before trying to include never before seen mechanics or reworking the class completely.