Statistically he doesn't look much different than he's looked the last few years (just his three point shooting is down). He's never been injury-prone so I think he still has 3-4 good more years in him. He carries around a lot of weight, but it's not really caused him problems.
He does have a lot of mileage on his legs, but Lebron is just not a freak athlete. he's actually a very smart basketball player so I think he'll be fine as long as he doesn't suffer a serious injury.
I just think the team needs to be constructed a certain way for him to succeed.
In Miami, he had Wade to carry the load on both ends. It took a lot of pressure of Lebron. Then the team was pretty much a bunch of shooters...so the spacing worked out well.
he's still good for it he's just taking it easy and saving it for the playoffs like he should.