Tar comp ? Wazzat ?
Regarding X-Wings : I agree, but the whole point of the thing is to roleplay (to me, anyway).
Regarding TIEs : Yes, we're not that far, structures are only 30-35% more resistant vs. fighter lasers than they 'should' be. It's no big deal really, if you say there will be balance issues then I believe you.
On the Interdictors : The big problem, as I see it, is you can only use SM outside combat. The Interdictors were designed to 'drop' passing ships into realspace (unnecessary in SE IV, since everyone is in realspace already) and to prevent enemy ships from leaving combat (also unnecessary, because you can't escape from SE IV combat once it starts, you can only try to run away using your standard drives). In fact, it's as if there were Interdictors present at every battle already !
If you give them WP openers and closers, they will be used to project attack fleets into the enemy's rear area, and that is not their role at all.