Wishing for anything less than omnipotence is suboptimal, there's always more you could wish for otherwise. If you want to do good, even if you wish for world peace & a cure to world hunger & cures for all disease... you'll still have general human suffering. And depending on the type of genie directly wishing for such things might just mean the genie eliminates the world! If you want to maximize the good you do, you have to be able to correct for any unintended consequences (or first wish to be able to know and understand all the consequences and weigh all possible choices).
Wishing for garden-variety omnipotence would be boring. Of course you can alter yourself to make it non-boring, and with my version of the wish I could certainly remove the challenge afterwards, but I'd that makes the wish itself less fun.