I play ranked matches to win (granted I haven't started ranking the ladders in LoL, but my SC II history speaks for itself), and regular matches for fun. If I feel like playing a tank, a jungler or an AP character, I will play it.
If your complaint is about people that b**** that no one picked a Tank or jungler, specially in normal, I agree with you. I'll play with whatever the f*** I want to. I hate it when people think I'm playing the game for them. Sometimes I want to test a build, and I probably won't do so well, leading my team to failure. We lost, so what? Cry me a river. If you want to play to win, with people who will spam wards across the map and play with optimal teams, go ranked.