Focusing on some traders and not bothering with all of them?

[xCrossFaith]

So since some quests give negative reputation with some traders making it harder to level them all, I was wondering if it's a good idea to just focus on 2 or 3 traders and leave the less interesting ones aside,   I'll favor M4's, Vectors, FAL's and so on, so could I be fine leveling up only Peacekeeper, Mechanic and Skier?  At least until the full game is out and no more wipes come  (This  would also be a perfect excuse to avoid doing "delivery from the past" since I find that quest  to be absolute garbage)

[Shortstacker]

Some are more important than others, therapist, peacekeeper and mechanic come to mind. Cheap ammo and weapon attachments.