So you want control of one back who's bound to break down in say 4-5 years over the value of 4 backs that are still going to give you value for the next 7-8 years. That's 21-24 years of back control between Ingram, Ivory and Cadet. Another good 2 years or so of Sproles (because he doesn't get the same wear and tear as AP or any other back), and another good 5 years of Pierre Thomas.
Not to be an ***, but aside from Sproles, to put it bluntly, the rest of your RBs are crap that can be found every year in the draft at the mid rounds and beyond. Don't get it twisted, Brees "eliteness" makes them a threat, otherwise you can find a Pierre Thomas, Mark Ingram, Chris Ivory, etc. on every team.
AP, on the other hand, is worlds better than them and would make that offense virtually unstoppable.
1)They also have Tobey Gerhart. AP is so good they dont need to use white bread, they stick with pumpernickel.
2) There will be other drafts where they can restock when its time.
3) AP is the best running back. You take him. If Drew Brees had AP it wouldn't actually be fair for what it would do for both the passing and running games.