Yeah. I got from Silver III to Gold III this season mainly with a duo partner. Top+Jungle was really good, don't know about the next season, because riot wants to make the junglers affect the game less.
That's bogus, I main jungle and I like playing high impact late game junglers, like Udyr. My only problem is when my team doesn't know what "play passive and farm under tower if you're losing" means and they try to fight a fed lane opponent and then bitch about not having ganks.
I'll have to find someone to seriously duo with, because all my irl friends are in low bronze and troll every game, and I'm actually serious about improving and I'd like to get gold next season, and having someone to duo with reduces the odds that there is a troll/feeder on your team.