This encounter is a nightmare. I had a small struggle with Anthracite and Nibbleh, but Ahoo'ru is making my blood boil.
Thamyor's video and Tramposzek's video are the only two videos I've found that have a hunter killing Ahoo'ru. Both of these kills were done with better gear than what I've got equipped right now, as well as before they nerfed Stampede.
I've had attempts where, like Thamyor, I'd come out of P1 at around ~55 to ~57 seconds and even as Beast Mastery, not have the DPS to down him before the enrage timer. I've been using a Core Hound so I can have a Bloodlust, but I'm learning more toward a Spirit Beast for Spirit Mend. I've been doing well when it comes to avoiding the stars in P1, but having to use Deterrence to prevent the application of the DoT via Divine Circle isn't helping my push for a kill when I have to use it, sit a portion of the duration and then cancel once I am out.
I am trying everything I have to push every bit of DPS possible during P2, but even performing a perfect execution in P2 doesn't get me enough to snag a kill. There's never anyone in the Brawl'gar Arena for decent buffs, so I'm usually left to my own devices. Nobody in my guild wants to just hang out in the Brawl'gar Arena and give me buffs, either, and I suppose I don't blame them.
At the moment, I'm either hoping to end the angel phase significantly earlier than 1:00min on the enrage, or wait until 5.4 and see what happens. It's a bit demoralizing, to be quite honest; to have come so far and be absolutely stuck on the last encounter.