Then why couldn't other bosses drop useful stuff? Tier 1 HM FP's bosses drops Exotech and columi(some of them drop columi belt/bracer) implants/earpieces, so Tionese can get upgrade from these bosses as well.
Rakata is not big deal now, even farm those Tier 1 HM and some weekly quests can get BH gears.
I believe the bosses DO drop useful stuff, for those players that are skilled enough to do HM LI without having a complete set of Columi.
And even if you do have a full set, the gear can also be used to upgrade your companions, making dailies go faster.
Let me draw a comparison to Story Mode TfB. The typical non-elite player
who goes into TfB, has probably completed:
1. Every T1 HM FP
2. HM LI
3. SM EV
4. SM KP
5. HM EV
6. HM KP
7. SM EC
This player has a very good chance of having 2-4 pieces of Black Hole gear and mostly Rakata on the rest. Yet the entire SM TfB operation drops Rakata and 2 pieces of Black Hole.
There is some content in this game that is difficult.
The gear rewards are important yes, but the more skilled you are, the better the rewards (i.e. you don't have to overgear it). I think this is correct, fair, just and right.
If you aren't as skilled, you have to overgear the content. This is one of the things that Black Hole comms allow you to do.