Seen some people without combat skills who got relatively badass, all things considered. But it certainly isn't easy.
I have a very hard time playing dwarves (I get bored with the single-mindedness and social implications that has). I can play half-giants, but not when people are staring at you waiting for the comedic relief; I play them as big dumb brutes who know they're big dumb brutes, so I kinda play them very sparingly as a result. I obviously have a hard time with mages.
I can't play desert elves well. I don't particularly enjoy the balance between iso and non-iso. I enjoyed them a great deal more when you could have your own tribe with your own limitations, so long as you weren't spewing mages out into the world willy-nilly; now they feel far too restricted in what you can and can't do (only in my head; I haven't actually played one in a long time, pretty much since they said no more self-tribe creation and recruiting).
I have, to this day, never played a merchant or craft-heavy character where a majority of their skilldentity was in crafting skills. I get really frustrated whenever I try. I find out a few recipes, then get hungry to find more recipes and get myself killed just out of the desire to find something unique and awesome to make.