I haven't seen casting being tied to STR as problematic. Each bit of casting stat is worth several points of STR because of burn resistance. And anyone who puts STR above Con for a caster has tons of points, total crap for other stats, or wants to die. A low Con character is punished even more by GT than in DnD: a lower Con means more MDT checks, which are doubly bad because of his lower Fort. In the game we just finished, the 2 characters with 12 Con probably failed at least 50% more massive damage saves than those with 14. Since INT is far more important for casting, and CON is required for survival, STR is tertiary at best. So on a standard array, the caster is probably looking at 13-10 STR (and, given the need for other stats, probably about the same with higher point buy). While that kind of score is perhaps more buff than most DnD pencil neck wizards, it's not out of line for a guy doing dangerous stuff where physical fitness is somewhat important. Especially since he won't be casting spells all the time, other skills and abilities (eg, beating people up) will be required.