I'd love to give a resounding yes, but he may have been a little fish in a big pond in WWE. I loved AJ back in the day with TNA, but lately (and maybe its a product of the booking/times) he's been a non-factor. So if he is really that good, his main event status in TNA would be undeniable. Unfortunately, it is not.
But obviously, it depends on booking and whatnot. His promos aren't that wonderful but JoMo and Shelton were over in WWE despite that. Also, who knows if WWE would allow him to do the springboard reverse DDT or the Spiral Tap or the Springboard 450... The appeal of AJ was that he could do anything & everything and had a good match with anyone. Not sure if the WWE booking (overbooking?) would cater to the strengths he showed in TNA.
Undisputed Rap King of the Misc
New Song: http://soundcloud.com/maxcaster/geno-911
based on promo ability i would say no, he doesn't have the mic skills of a cm punk or likeability (lets get behind the underdog spirit) of a bryan danielson, he would probably be booked in a similar position to evan bourne then again he never took a chance so we don't know, how many would have predicted that jericho, mysterio, benoit and guerrero would all become big stars in wwe say in 1997...
Depends on your definition of "made it." I could see him having been a rich man's Evan Bourne/poor man's Rey Mysterio... IMO, there's three key categories: size, charisma, and in-ring skills. If you have 2/3 and some luck, you can make it. Styles was incredible in the ring in his prime, but never had much charisma and obviously not size, either.
AJ would have ended up just like Paul London. If either got the chance in the E today rather then 4-5 years ago or w/ e it was when they were the hot thing on the indies much like Punk, Bryan, and Cesareo were right before getting signed more recently maybe things could have been much different.