creeper spawning setting for minecraft worlds

I think many people will agree that Mojang should add a option to the advance world settings that affects creeper spawning. This is a good idea because then some people who hate creepers including me will be able to stop creeper from spawning without using cheats. also then make it so that zombies can drop gun powder (only if creepers can not spawn anymore) so that we still have a way to get gun powder. also to make the lore clear why zombie will now drop gun powder is because they have been raiding dungeons since there are some zombie spawners in dungeons just to make it clear ;)