The problem there (with giving them points values) is that I wouldn't really want them drifting into general play. Customisable heroes are very hard to balance across X ships times Y special abilities..... in a campaign, that's fine but not in "normal" games.
I would like to see it done on cards. One of the big advantages of X-wing is that there's very little book-keeping, and a unit is a unit card plus (maybe) two to three upgrade cards, nicely printed with artwork and all the rules immediately to hand.
I can see something similar in a 'campaign' set - one "Hero" card per squad to be 'you' and maybe one "Wingman" card* to be your buddy. Initially free, with no real advantage, and must be attached to a non-unique pilot (you're developing the story of your character - named pilots have no real place in this!).
The Hero and Wingmen cards let you attach some extra abilities to the fighter they're bolted to - not standard upgrades, but things unique to and linked to the campaign...so, for example:
If your pilots get killed, you can take cards like:
Rookie Replacement.- Rookie's luck (rerolls?) at a cost of pilot skill
Bionic Hand - Some sort of immunity to stress
Near Death Experience - Give you more defence dice as you get closer to being shot down again
Seek Revenge - get free target locks on the guy responsible?
If you got kills
Don't Get Cocky - get some sort of free focus
Learn Quickly or Die - gain an elite pilot talent
Customised Fighter - gain ???? (Some sort of upgrade slot)
etc, etc. You essentially get one new card per game you play in, from a list depending on won/lost, survived/shot down and scored kills/no kills, up to a limit of maybe three cards (more than that gets too many special rules on one guy for this game) - although you can substitute cards based on later games. Essentially the cards build up a 'narrative history' of your pilot's achievements over the course of the campaign.
* You might say that you get one 'wingman' if your 'hero' is in a 20-25 point fighter, two if he's in a <20 point fighter and none if he's in anything more expensive; hence providing a balance if one player wants to take a rookie TIE fighter squad and the other wants to be in an E-wing....