I would argue that Wade has already been in the same class as Lebron and as of right now is possibly better because of one factor: defense. Lebron's effort on the defensive end is average at best (most of the time it is absolutely nonexistant) whereas Wade has gradually improved and made big stops throughout the playoffs in critical moments (he has worked with Payton and is training with Kobe over the summer). There is no question that Lebron has the most potential of the two simply because of his size and athleticism; in fact, he could be a ridiculously good defender if he puts those gifs to use. However, until that time comes, I believe Wade is the better player because he gives it his all on both ends of the court.
On top of all that, there is one other huge factor that pushes Wade past Lebron: shot selection. Wade rarely - if ever - takes bad shots and shoots at an extrmely high percentage whereas Lebron often falls in love with the 3 ball instead of driving to the hoop like he should.