Orcs are indeed playable. You aren't screwed just because you have a 15 or a 16 in your casting attribute. Heck, even 13 or 14 is good enough. I've played several orc PCs (most of them casters) and they're all pretty powerful.

I have an orc druid who started with 20 Str and 15 Wis at level 1. Other stats were between 7 and 13, so fairly average. While I play him as a fighter, he's still a competent healer. Gotta use the Str bonus to your advantage.

Also have an orc sorcerer (who uses a greatsword!) that I also play in a similar fashion... there are plenty of sorcerer spells out there to make a character a decent fighter.

They're certainly not the most effective combinations (or even setups) but that's the sort of thing that differentiates these PCs from your everyday sorcerer or fighter. Just have to be creative.

+4 Str is a wonderful thing, though... It's hard playing an elf or a human after that. Once you go green you never go back, I guess.