Why the desire for low magic?

[Crake]

Yes, that is the problem with the Fighter. His existence means that certain kinds of compelling, engaging encounters can't happen, because he doesn't not have the abilities necessary to contribute to them.

Fighter's not the only one though. If your challenge requires magic to solve, there's a whole slew of classes that can't contribute, and if your challenge doesn't require magic to solve, then it's not a high magic challenge, so sounds to me like the limiting factor is more with high magic challenges than with the whole array of non-magical classes.

Also note I never specified fighter, that's your own inclusion.