Hrm, I just found out about this myself, and from what I have gathered from
here, it looks like fun, in a simplified-but-not-the-way-4th-edition-did-it way.
That link has the quick start rules, that cover Fighter, Cleric, Rouge and Wizard to 6th level(except spell details)
also the "Why Play Castles & Crusades?" section has compiled a bunch of forum posts about it; that being said, I didn't see any optimization on those forums at first glance either.
It looks like you pick a class, pick a race, pick your "prime" stats then go play... there are no skills, at all, everything is based off of your stats. As far as doing what we are used to skills and feats allowing in game, you can try to do anything, and it's more likely to work if that action is determined by one of your "prime" stats.
As far as balance between casters/non casters, the classes level up at different rates, so it's hard to tell just by looking at the quick start guide. I did see alter self and polymorph mentioned though...
one more thing, they claim that you can use all the old AD&D stuff with it, by determining most C&C stats from the HD, and 3.X
allegedly requires only a little more work to be compatible with C&C.