A good way to judge it is to compare several equivalents:
- Soontir Fel - Royal Guard TIE, Push The Limit, Autothrusters, Stealth Device
- Blue Ace - BB-8, Primed Thrusters, Integrated Astromech
- Duchess - Adaptive Ailerons, Veteran Instincts, Lightweight Frame
If people really thought that pure manouvrability won games so effectively as to be a negative experinece foe the other player, people would be complaining endlessly about blue ace - who's stress-free daredevil and ability to talon roll then pull a 90' boost is just insane.
If it was a mix of repositioning and pilot skill, duchess - who has the same repositioning ability as soontir fel, doesn't have to deal with stress (allowing you do use the white moves as well as just green) and has PS10 to give you the edge even over PS9 opponents, for cheaper than Fel, would be public enemy #1
They're not.
This is because the 'aces are unbeatable' feeling only comes where you have repositioning abiltiy and high pilot skill and the ability to rack up massive stacks of green dice and green tokens - a feeling that you've outthought your opponent, got 2 arcs of fire laid on them despite any repositioning actions they might pull....and they go "what's your point?", dodge both attacks and don't even lose their stealth device.
They're not unbeatable - especially with stress tricks (assaj, slicer tools, latts, R3-A2), anti-dice modification tricks (omega leader, crack shot, 4-Lom, homing missiles) - but they can - certainly did at the height of palpatine and his evil dice ju-ju - leave people feeling that whatever you did, the aces got to decide after you acted exactly what they needed to do to avoid any choice you made having been worthwhile.
It's the same issue people had with the "quantum phantom" which retroactively turned out to have decloaked exactly in the right spot to avoid your kill boxes.
The change to the phantom - where you had to plan your decloak - and the change to Palpatine - where you have to commit him before you roll - requires you to excerise a bit of judgement and take some risk, which feels a lot better.
It's the reason I won't complain about bombs and mines. Yes, Sabine is bloody annoying, and I hate K-wings with a passion, but I won't and indeed can't say they are an NPE - they rely, entirely, on your flying (and predicting mine). Winning with them specifically requires you to outfly me; I have only myself to blame.
As noted, they did always have weaknesses, too. A fully tooled up soontir fel was still not massively shootier than, say, a 17 point TIE striker.
Edited by Magnus Grendel