I agree, some of the biomes are just silly or cluttered, and don't even get me started on the colors.
A lot of biomes o plenty is just to busy for me, if you know what I mean. There's too much stuff everywhere that has no real purpose and just serves to clutter things up. The sky colors really, really annoy me and I don't like most of the grass or rock colors either. Some of the biomes are really cool but I don't like a lot of them. Some of the biomes are kinda ridiculous, and a lot of them are magical/fantasy biomes, which i'm not a huge fan of.
I suppose I'm a bit biased towards highlands though, I tried it out and fell in love with it pretty much instantly. I've yet to find a single biome that I don't like and it has some really neat features.