Ah, so you hang around Open Game Art too. In that case you've probably noticed how pretty much everyone there agrees that CC-BY-SA is not viral, unlike other copyleft licenses. To be sure, the ambiguity will still discourage some buyers. Namely, big commercial interests who would otherwise be all too happy to exploit your work. Those won't touch CC-BY-SA content with a ten-foot pole... which is probably what you want.
As for the risk of people reselling free culture works... how often have you heard of it happening? People are more likely to try and resell games that aren't under an open license. In fact it was a series of such cases that forced us to introduce controls. Seriously, reality proves again and again that it's people who believe copyright equals property who will, you know, steal creative works.