LostSoul
Adventurer
I see two different readings for the second statement, and I'm not sure which one you meant. You're certainly not obliged to change the system. Many people have played it as is, and for many no problematic power gap has come up. Even if you do have a large power gap, Dannyalcatraz has talked about running a vagabond and a glitter boy in the same party successfully in RIFTS, which is a larger power gap then you can get reasonably in D&D 3.5. And even if the power gap occurs, you can avoid it by restricting which classes, feats, books, etc. are used, or by purely social mechanisms, by producing characters with an eye to avoiding the power gap.
I only meant that you might have to change the system if you want to avoid the power gap, not that you had to change the system in order to enjoy 3E.
I don't think the power gap is always a problem. The worst thing that can happen is that it robs PCs who don't have high caster levels from making meaningful choices; that can be dealt with by a well-crafted setting where there are multiple avenues of action. I don't think it's too hard to build that kind of setting - the default one suggested by the DMG's demographics should suffice.
For example, I don't know what I'd do in my current 3.5 game to deal with the threat we're facing if my PC was a pure fighter. Since we've got a rich setting to work with, though, I could probably come up with something. It'd probably be more difficult, sure, but that's not a problem.