This suggestion is very simple, I think it would be very useful in certain servers and nothing really difficult to do...
It would be to implement a biome compass. For example, I play in a recently created pixelmon server, in the Spanish community http://www.deadplayers.net/#, and the server has 3 worlds, the spawn world in which pokémon spawn, a world where you can place a protection and build a house and a world for resources. The thing is that that the spawn world is big, but at the same time limited, and has most of the biomes in which pokémon spawn, but I can't find certain biomes such as Extreme Hills +M, Mesa Plateau M, etc.
So I think that a great idea would be to create a compass that when you click it shows up a list of the biomes, you choose the one you want and the compass points towards the closest one, so you still have to explore in order to find it...