new trees
like the forest trees in the mod: ExtraBiomesXL
http://www.simulatormods.com/wp-content/...-1.2.3.png
villages + villagers
Desert Biome
(don't know if it is difficult but it is only sand + some cactuses
plugin to change weather (McRainbow doesn't work anymore
)
mobs that spawn in caves
the mobs now don't spawn under the surface 
abonden mineshaft (i think that it would be difficult)
these are only ideas
maybe more??
like the forest trees in the mod: ExtraBiomesXL
http://www.simulatormods.com/wp-content/...-1.2.3.png
villages + villagers
Desert Biome

plugin to change weather (McRainbow doesn't work anymore

mobs that spawn in caves


abonden mineshaft (i think that it would be difficult)
these are only ideas

maybe more??