Yes, I do. His stats will improve in time. Barring injury, he's never going to have a regular season where he's under 60% completion again (last time: 2007), he's going to throw for around 4,500+ every year, and he might have just one 20 INT season for the rest of his career. With the receiving core he has around him, there's just no way he's not capable of this.
What do you mean by 4th quarter comebacks in this age? Only 19 out of 104 quarterbacks with 10+ 4th quarter comebacks are active players. Five of those guys are near retirement: Jeff Garcia (41 y.o.), Donovan McNabb (35), Jon Kitna (39), Jake Delhomme (36), Kerry Collins (39) Matt Hasselbeck (36 and the only guy in this list who can still legitimately start in the NFL). The only guy who's really pulling comebacks out of his ass today is Tim Tebow.
Am I saying it's the most important characteristic? No. Aaron Rodgers just blows teams the fuck out so he's rarely put a position where he can complete a 4QC (he only has 3 in his career). But, it is something Eli is known for doing and it's the quarter that the guy shines brightest in (as highlighted by his performance the entire year).
By the way, Carl Pickens is a horrible comparison for your point because he only has one 100 reception season. And yes, I am nitpicking that 99-rec season. :lesmug:
You were looking for either Herman Moore (3) or Wes Welker (4 and a FAR better comparison).