I actually enjoy Nemesis Mode
After briefly looking through the boards, I noticed a lot of threads which expressed unhappiness with Nemesis mode. Now, I can easily see where they're coming from, but I figure I'll give my take on it so Riot doesn't think that they created a game mode which nobody enjoys.
In a game where deviating from the meta is next to taboo, it was nice to have a chance to play where trying something new is effectively sanctioned. I had always wanted to try AP Nami and Alistar within a game, but was worried that I would feed horribly and cost my team the game; now, thanks to the new mode, I got my chance. I've played without a jungle, played against double jungles, and seen some pretty crazy builds when people had no idea what they were doing with their champs. And I had a good time doing it.
Sure, there are some rage-inducing aspects. But overall, I have been enjoying it and seeing the inventiveness that people come up with when they don't have a say in what they play.