he T-70 X-wing, starting with 2 XP, would also probably be fine in terms of balance; my issue with it is that it's strictly superior to the T-65. While other ships require you to trade off some of the things the X-wing can do, the T-70 does everything better. I'd go so far as to say you might as well ditch the T-65 altogether if you're allowing the T-70
Most of the deficiencies of the X-Wing are addressed by the HotAC game itself with modifications and such. I don't even see the point of including the T-70 at all. You pay 5XP and get 8XP worth of upgrades for free, the Tech slot, and an upgrade to the movement dial, and you get two modification slots back (Shield Upgrade and Engine Upgrade).
*snips a lot of overenthusiasm*
Unless you're massively altering the way the missions are configured for Difficulty Level, allowing players to use higher tier ships is basically setting the game to Easy Mode. A PS6 player with an E-Wing is going to wreck shop, since he likely has Boost, Barrel Roll, Evade, 5 Shields and 2 Hull, Regen, a System, and two Elite skills/talents (swap a shield for Autothrusters by preference). His X-Wing buddy with the same card selection has Boost, Regen and 3 Hull/4 Shields and 2 Elites. It's not even comparable, lol.
That's rather vitriolic and VERY negative - and there ARE other ships. I personally can't imagine playing anything but my Moldy Crow focus passer; now THAT'S going to be OP once I get Garven's ability!
But if they aren't balanced against the regular ship, we can MAKE balance. Perhaps the straight better ships - T-70, Starviper, E-Wing, K-Wing - can do one of the following:
1) Pay double XP for any upgrades to restrict their options early on
2) Pay 3x the cost of new PS levels to upgrade, which would slow them down versus other ships and make time spent in the 'lesser' ships attractive
3) Get fewer EPTs in order to make the other ships more attractive for comboing abilities
4) One of those 'advanced' ships counts as .5 players on a team, and if two of those ships show up then it's +1 player with all that entails for more Imperial ships...
But SOMETHING can be done.
Giving up and saying, "They can't be balanced! You're crazy for including them!" is pretty defeatist and cuts against my grain as a designer.
I think I like 2, 3, or 4.