The Big Show, to me, looks about the same as he did during WM 24. He isn't anywhere near as heavy as he was when he left the WWE a few years ago. During WM 25, when they showed some video footage as part of a build up with the triple threat match for the WHC, they showed some old footage of Cena with Show on his shoulders to deliever the FU. The announce teams keep saying he's about 485 lbs, I don't really know why, because it's just not true. I remember the show when he was that heavy and he just doesn't have that much poundage on him. He might not be quite as firm and tight as he was, but I don't really think he's any heavier. A lot of people are a bit too hard on the Big Show, in my opinion, because of his weight. For one thing, Vince wants him to be much heavier than the average WWE wrestler but, at the same time, Show's not going to have a bodybuilder-ish type of physique. I've seen a couple of old photos of the Great Khali back in his bodybuilding days and he looked downright freakish. He was much more cut now than he is today and that's because his entire life revovled around eating and exercise. In order for the Big Show to really do anything similar, he'd have to be eating and working out almost constantly in order to turn his fat into muscle and to maintain the size that Vince would want him to. It's just not possible to do with the road schedule of a full time wrestler.
As far as a push goes, I don't think the Big Show really cares either. While he was gone, every interview done with him after he left the WWE suggested that he was as happy as a bird in a tree. He'd saved his money, was careful, made some sound investments, etc. Vince must've offered him a pretty good deal to get him to come back.