Quote from djtanng
I know that things like added structures will be different, but I'm talking about the generated world in general. Say I have a seed with an awesome mountain with 3 waterfalls. Will that same cool mountain with 3 waterfalls still generate if I restart the seed in TU14?
Yep, biomes won't shift until the 1.7 PC equivalent update. Since we are getting 1.3.1 in TU14. Biomes will stay the same for a long time to come.