I know what you mean. Seeds are pretty much useless now. Although I think too many options would bork stuff like servers. I think they should globally change the world generator for the better. AKA: Either 1.7.3 world generator with the new biomes or something better.
I especially miss being able to mine without hitting a neverending cave, beaches, gravel beaches, hills in a forest, not having sudden mountain spam, hilly snow biomes, large lakes, small ponds without the ugly splotches of clay and sand, and biomes overlapping with each other.