If you're having trouble using the QQB in its current state then you just shouldn't be using LMGs.
It's not about trouble, just the principle of the fact that the QBB is the most CQC-inclined LMG, yet counter-intuitively, it was the only LMG they didn't reduce ADS time for in the January patch. While the QBB may have very slightly less recoil than the HAMR, this is insignificant outside of longshot range and the HAMR has a 3-shot range twice that of the QBB, which is very significant. The QBB also doesn't have a headshot multiplier, unlike the HAMR. The HAMR has the function of dropping in firerate for sustained long-range combat, which when combined with its higher range and headshot multiplier, making it much more versatile than the QBB. Again, the QBB is also the only LMG that didn't get its ADS speed decreased.
It's just an oversight in weapon balancing. Treyarch has done a great job with BO2 and the balance issues are nothing compared to previous games' problems, but the pursuit of perfection should be endless, especially if 3arc wants their game to be an eSport. Did Blizzard ever call it quits after half a year of tinkering with an RTS? No, they fine-tune their games for years and the tiny issues that are left over afterward are still a big deal in competitive scenes.
Speaking of AR/LMG hybrids, I find it funny that the SCAR-H is an AR while the SCAR-L aka HAMR is an LMG.