If the Gm picks my stats for me id require a stat of at least a 16 because if im a caster im royally screwed and i am of no use to my group if i have a low casting stat. And I also agree with the fact that it is your character not the DM's character so i hang on both of those aspects to be honest.
Also i get there is role playing, but what about combat? Low Fantasy games are very dull to me and id rather play a caster because i can do way more with them later on (if my score for that stat doesn't suck.)