Options I had been toying with as house rules were allowing the Y-Wing to choose a Heavy Laser Cannon to replace the Ion Cannon. That is you can have one or the other and/or allowing a crew member so you could fire the Ion cannon and primary weapon in the same turn.
Both options are within the canon of the Y-Wing descriptions for load out.
The heavy laser cannon would still be 7 points and follow the firepower and range requirements of the current cannon, but be turret mounted.
The cannon would also only be an option on named characters and Grey Squadron, to stop 4 Heavy Cannon ships being on the board.
You could make a nice balance with Y-wing squads then.
(I personally don't think the Y-wing is broken, but it certainly might get more flight time with a few more options)