Board Thread:General Discussion/@comment-27255668-20160105023421/@comment-25926288-20160105023728

Wishes can kill. Noone said that they couldn't. Just couldn't bring them back to life.

Noone says a genie is invulnerable. It is presumed that if Will's heart was crushed, he would die and the killer would become the genie or it's simply void.

So, none of them are plot holes.