When I play, I mostly do things that really isn't possible in normals. AP Ashe, Lucian and Miss Fortune for example. None of them are broken, but jesus christ they are SO fun to play!
What mostly ruins URF for me is that people just pick what is most broken and abuses it. Zed being an example. He is more or less completely undefeatable lategame, and it just isn't fun to play against (I'm banning Maokai btw, I'm not facing that shit again).
Back in 2014 when it first arrived, it was just SO fun. I've never had as much fun in any videogame than I had back then. Sure, some champs were completely broken (Hecarim, Kassadin etc), but they got permabanned by Riot.
It's not possible at all for me to play anything that isn't broken as fuck, because everyone picks it and I'm not allowed to play.
Riot should have permabanned some champs again.