At this point I'll take any writer who's
A. Actually invested in Tony as a character and in telling stories with Tony.
B. Will actually and effectively use Tony's supporting cast (and not characters they shove into the supporting cast).
C. Somebody who actually gets Tony.
D. Can tell good and effective Iron Man stories.
Slott's Parker Industries storyline felt like an Iron Man parody/"homage," but he would still feel like a random choice to take over the actual Iron Man book.
I don't think he'd be a good fit otherwise.