Dolph Ziggler has nearly all the makings of the next big superstar. He's extremely talented in the ring, very good on the mic, has a solid look and good gimmick, and he is already attracting heat like crazy, though Vickie Guerrero deserves some credit for that one. The only thing holding Dolph back is his size.
Dolph Ziggler has put on a couple of great matches with Daniel Bryan, a wildly entertaining match with Kaval, and multiple entertaining matches with Kofi. He seems to work very well with other quick, agile, smaller men.
His work with Cena was very good. I was only able to catch his match on RAW which, while a little long for my taste, was very good and both men came off looking great. That said, it didn't quite have the same feel to me as the matches he had with DBD, Kaval, and Kofi. While his match with Cena was good, I never got the feeling that he had a chance. This could be simply because Cena is the top man in the company and Dolph Ziggler is the upper-midcard at best, or maybe it's because Cena is huge and Dolph Ziggler is comparably small, but either way, it's someting that's going to need to change for Dolph Ziggler.
With Miz as WWE champion, there is hope for Ziggler one day becoming a WWE or WHC himself. Miz isn't the biggest guy on the roster, and it opens up the possibility of having other mid-sized guys winning championships. (I know Rey has won the WHC recently, but Rey is a very special case as they have had him take down big men before.) Now having mid-sized guys win the WWE and WHC title is nothing new, guys like Benoit, Eddy, and Kurt have done it before, but in the past 2 or 3 years, the majority of champions are the huge guys like Cena, Batista, Orton, Edge, and Taker. If the WWE is going in the direction of giving the smaller guys a chance to hold the title, I don't doubt that Dolph Ziggler will have a reign as the World Heavyweight Champ.
Even if he does become a main event fixture, though, I doubt he'll ever be the WWE's big thing. I don't see him breaking into the top five of WWE superstars for more than a few months. Randy Orton, Daniel Bryan, The Miz, Wade Barrett, and Kofi Kingston are all 30 or younger, and I think all 5 of them will wind up (some already are) being more popular than Ziggler. Furthermore, CM Punk, John Cena, John Morrison, and Sheamus are all just over 30 and will probably be in the WWE just as long as Ziggler, and I think all of them are ahead of Ziggler in the pecking order.
Dolph Ziggler has shown us a lot of good stuff in the past few months, but if he wants to be the next big thing he's going to have to show us a lot more and prove that he deserves to be in the main event more than the likes of JoMo, Kofi, Sheamus, and Daniel Bryan, which is an extremely tall order.