If Barbossa and Jack could have come back from the dead why not Will? That way Jack could have stabbed the heart himself.
First, the crew of the Dutchman aren't dead and neither was Jack. The crew is cursed, but supernaturally alive.
If Jones remains alive, Will was to have become part of the crew, not left to suffer in Davy Jones' locker. Rescue from under Jones' direct thumb is conceivably more difficult than rescue from a distant, unguarded prison.
But more than that, while Jack wanted control of the Dutchman, he was not keen on the chance that he might become cursed as Jones had been.
Remember, Jack only wanted the heart to get out of his deal with Jones. By allowing Will to become captain of the Dutchman, his deal with Jones was concluded, and he does not have to chance being punished by any curse and becoming a sea-monster of sorts.
From Pirates of the Caribbean: At World's End:
Jack: Let someone else dispatch Jones.
Will: Who? You?
Jack: Death has a curious way of reshuffling one's priorities. I slip aboard the Dutchman, find the heart, stab the beating thing, your father's free from his debt, you're free to be with your charming murderess.
Will: You're willing to cut out your heart and bind yourself to the Dutchman... ...forever?
Jack: No, mate. I'm free forever. Free to sail the seas beyond the edges of the map. Free from death itself.
Will: You have to do the job though, Jack. You have to ferry souls to the next world. Or end up just like Jones.
Jack: I don't have the face for tentacles. But immortal has to count for something, eh?
In short, letting Will stab the heart, he gets everything he wants with less risk.
I got the impression that he eventually wanted to stab the heart because of the immortality that comes with it, hence his quest in the next movie.– AyrxJun 6, 2014 at 16:58
1@TerryChia, yes, Jack wants to be immortal, but my interpretation is that the risk/reward for this particular method was just too great. Even through the movie, the immortality is clearly a secondary motive for his actions. His first and foremost is getting out of the deal with Jones. Jun 6, 2014 at 17:01