Psion
Adventurer
Mishihari Lord said:I'm going to have to disagree with you on this one. Most of the books I think of off the top of my head include more flexibility in what magic you can do and the idea of fatigue being the limiter in what you can cast.
Most of the books I can think of (including some on your list) may give a few throw away words about it being taxing, but nothing saying what really is a hard limit. So basically it comes down to authorial convenience.
Since an RPG is required to be more rigorous in this regard, I don't exactly fault it.