Don't underestimate the value of the Jetpack. Remember in the GCW era, nobody can really fly among the normal units (the DT is just a jump jet). The Jetpack is a huge advantage in movement, and since going after control points is your primary concern, it's quite an advantage!
Solo's/Leia's pistol is powerful, but then so is Fett's rifle. Everybody uses the flame rifle because it's more fun, even though it is actually weaker (like the Bothan Spy's "heat gun", heh). And Fett, unlike the DT, has wrist rockets (equivalent to the ones used by Super Battledroids).
But you're right... never underestimate the power of the fett wankers...
There is currently no way for Fett to fight a Jedi in the beta. That will have to wait for the celebrity deathmatch mission, or perhaps some map that pits a Jedi vs. Boba or Jango. His opponent on Utapau is Han Solo, and that's it. In any case, if he were to face a Jedi, he could easily escape from him via his jetpack to get out of range and away before they can get him. He can go places no Jedi can get to, in terms of height (Force Jump is nothing compared to the ability to fly).
Will more fans choose one over the other? We'll see.
But the map and side determines whom you get to be, except on the Celebrity Deathmatch mode (which isn't playable in the beta). The Villians side has two flying dudes on board, but then the goal is to get kills, not capture control points, so I don't know how it would end up.