I've had a 7D and a 5DII. I much prefer the IQ of the full frame camera to the speed and AF abilities of the 7D. I loved my 7D but full frame game my pictures that extra wow factor IMO. It's hard to measure the impact that bigger sensor has.
All this does it put numbers to what we already knew. When you put a lens on a D800 and a 5DIII and go out and take pictures the difference in IQ (specifically resolution in this case) is not as large as some people would have you believe. Both cameras are great. It's not worth arguing over. The only reason one needs to compare cameras is if one is going to invest in a new camera system. In that case, one should rent the cameras in question and decide for himself which one best fits his needs.
If it were to have 11 cross-point sensors I would seriously consider buying it. Assuming it doesn't, 5DIII is only upgrade from my 5DII. That's a real shame to me. I can't believe they cripple the autofucus once again. The 60D, 50D, and 650D all have better AF. Why?
70-200 2.8L is hands down the way to go IMO. In the style I shoot it is a must have for weddings. Spends most of the day on my camera. And you have a very similar setup to me on the shorter end. 17-40 and 50 can do everything you need.
i truly believe the move to FF makes a huge difference. the iq is unquestionably better. in my opinion it takes your photography to a different level that is worth the money. it allows you to get shots you couldn't get before and that is worth an undefined amount