Basically the official answer to this is non-class specific tokens with Campaign gear. AKA we screwed up but we're not going to fix old content.

No shotgun because you can swap barrels from OH to MH I am guessing, and no VK because agent mirrors smuggler.

Wrong. Right.

Well black hole doesn't have set bonuses, campaign does. Also the set bonus hasn't changed and I reaaally doubt that you can stack identical set bonuses.

It was reverted on PTS before 1.2 went live.

Well, that's because they've never had to. Just saying.

The set bonus is not supposed to transfer. Not sure how, or if, it did for you yesterday. Pre 1.2 gear the set bonus is on the shell, post 1.2 the set bonus is on the armor.

Leveling they take too long to assemble and complete, I don't even bother with the heroics most of the time due to being poor returns for my time. At 50 they're about the worst way to pick up gear, on HM most will take an hour or so to do plus finding the group and ONE of you get a Columi piece. One good evening of ops (EV, KP, and first 4 bosses of HM EV got me 2 rakata, 5 columi, and a piece or two of exotech + comms) will gear you as much as days on end of HM FP's. Regular FP's are a total waste as they rarely give you anything notably better than the lvl 50 purple mods in orange gear that anyone can farm with dailies and buy off of GTN. I can see them being fun for people that are just playing for fun, but if you're trying to get the gear to go on to HM FP's, ops, HM ops, and so on they are almost pointless outside of doing the daily/weekly HM quests to get some extra comms.