In zero gravity? No. In low gravity? Maybe.
It'd be interesting at the least, and much easier. Arrows would go straighter, you could hit the healing things easier and you could get right up next to the dragon with your sword.
How cool would an Ender's Game theme mod/texture pack/pvp server be? All the mobs are buggers, zero g in "battle school" perhaps a pvp battle school game where you need to get through the portal "the gate" to win...
thanks for the ideas guys, hope this actually happenz