Some very good answers so far...the removal of intolerance, greed and hate. Removal of all pollution would be good too, but i'm afraid we would just Re pollute without changing something of ourselves?
I might choose the removal of EGO ?.. anyway, the kind that makes people feel a need to be richer, stronger, prettier, or "better" in some way. But, maybe Ego is one of the driving forces of man'kind' ? Maybe it's a factor in someone building a better mousetrap or other inventions?
I might choose the removal of Fear, because i'm convinced that hate is actually Fear, turned outward!
But, without fear, could we have even survived our early beginnings?
So... i dunno. Maybe the removal of UNHAPPINESS ?... i think we might be able to do without that?