I do believe the O line is hindering Eli and even with their better play as of late, Eli is still shell shocked and not as comfortable in the pocket as he's like to be. Unfortunately, for the aforementioned reasons I stated, I think taking the hypothetical path the OP presented might be a risk worth taking. Eli is not going to get exponentially better and I'm not into winning a SB sprinkled with atrocious seasonal play around those years.
We don't know if he will be this super saiyan QB with a better line, but I know how well he plays when he has time. That's all I need, and I'm willing to give Eli another year with a better line. Why would you also put an unproven 1st round QB behind this atrocity anyway? Doesn't make any sense.
Just going back to the comment about Eli "just being a downfield passer with most success with huge receivers". Not sure who it was so sorry for not quoting directly...
..but we've had some of the gaudiest (sp) WR number in Giants history with Smith (5'-11") Cruz (6'-0") and Nicks (6'-1").... and with 2 of them playing out of the slot.
That perception just doesn't match the reality.
Like I said before, to many factors impact the results of whichever decision you choose, but purely based on talent replacement and possibilities, I think it's a no brainier to risk on a draft, assuming there is a top prospect like that available.
The Giants have greater needs than QB