Finished off 4/4 rank 8 yesterday as Enhancement. Killed Millhouse, Zenshar and Epicus ~1.5 weeks ago and had so many wipes on Disruptron I literally lost count. Like 50+. But with a littlelot of RNG and managing not to play like a scrub I managed it. Here's some general notes for anybody who's trying it as a melee rather than ranged.
-Levitate is your friend. Yes, people will be looking down at the use of it, but it's not been 'hotfixed' yet despite various other Brawler's issues being addressed, so I'm considering it Working As Intended for the time being. Plus, I find it hard to believe a single melee has killed it without levitate; I think it's mathematically impossible without literally the best RNG as far as cannon activation, positioning and beams you'll get.
-Primal Elementalist/Echoes of the Elements is the spec I used.
-Start the fight with a prepot, put Searing Totem, Earthbind/Grab Totem and Capacitator Totem down. As soon as the stun expires, put down Earth Elemental. I was swapping to Fire Elemental and a snare totem at 65% or so- possibly a little lower would do no harm but definitely not higher as you want the Elemental up for the <35% burst.
-If Penta gets activated, just give up. No seriously just wipe and try again. Even if you do dodge it you waste so much DPS time you'll hit enrage. The amount of uptime you have on this boss has a massive impact on how it goes, and getting penta-cannon just screws you so badly, especially when afterwards you get a Tri-cannon and he just STANDS STILL IN ITS PATH.
-<35% is where it matters. RNG is a huge component; you want him standing at either the the north or south wall- ideally South (as you are spectating). This is because at this point you stand at the wall, pop Heroism, Ascendance, Stormlash, Wolves, second pot and just nuke him from range. Standing in the middle of the wall means the only thing you need to do is dodge left/right from the penta's rings- the rest won't touch you. If he runs out of range, you're kind of screwed. This RNG is the hardest thing tbh- if he's in the right place you can literally just truck 30% of his HP in Ascendance.
-The last 10% is just a leap of pure faith. Wait for a penta shot, run in to melee when Ascendance is off, and just finish him off. Pop Astral Shift, Sham Rage, Ancestral Guidance and pray you're in a good place for the few precious seconds you need.
I wish any other melee the best of luck with this; I've only heard of a handful managing this fight and it is a total bitch. Note it also requires overgearing to the hilt even with levitate, 10million HP when you need to run around like a headless chicken is not forgiving!