Stop "fixing" ships with power creeping gimmicks that over-complexify the game, and re-think ship prices.
Edit : anyway, please, anything but S-foils. X-wings are not stupid flapping birds, on combat situations, those things stay open, period.
There seems to be a more fundamental problem with the X-Wing than its cost - and it's the same reason why the Kihraxz, and even the previously solid B-Wing, are suffering at the moment too.
It's simply that Arc Dodging is a more effective strategy than Jousting.
So having a 19-20 point X-Wing that can't tag an arc dodger and gets chewed to pieces by OOA shots isn't a great improvement on a 21 point X-Wing that can't tag an arc dodger and gets chewed to pieces by OOA shots.
One solution is to turn X-Wings into Arc Dodgers, but homogenising the ships so they all work the same way is kind of boring.
Another approach would be to make Arc Dodgers less effective against Jousters. Kind of like how Autothrusters brought back the balance between Arc Dodgers and PWTs by forcing PWTs to play away from their strengths.
So maybe the way to think about it is to make it less attractive for High PS PTL-ing Aces to arc dodge you and force/encourage them to take you on head on - playing to the strengths of jousters.
Something like:
Stabilised Rear Deflectors - Modification
Once per round, when an enemy ship outside your firing arc declares you the target of an attack, if you are within that ship's firing arc, immediately assign it 1 stress token.
You may not equip this upgrade if you have the boost action.
or maybe
Once round, when an enemy ship outside your firing arc declares you the target of an attack, if you are within that ship's firing arc, place 1 additional shield token on your ship card - even if this exceeds your shield value - if the attack does not hit immediately remove the shield token.
You may not equip this upgrade if you have the boost action.
This is a good idea for a modification for any jouster type ship. I like the 2nd one better though. It might be too much to punish a ship for arc dodging. But helping a ship that got arc dodger might be ok. And it would definitely help low PS generics more. It probably needs to be tweaked a bit, but it is intriguing.