They are currently trying to adjust the Mechagon key in preparation, but from what I have read it'll still most likely be a dead key. The mechanics are just over the top to finish it compared to others.

Currently running 5 druids and working on pushing my team more. For some reason I've been hesitant. I tried my first +7 last week (Freehold) with Volanic and finished with 5-6 minutes to go. Volcanic was a terrible affix though, and for my team which it's a massive loss of DPS due to not having good mobile DPS.

I think this week is a bit easier so hoping to give it a few more tries depending on how much time I get this weekend.
The other team I have which I've sort of benched is Brewmaster / 3x Hunter / Resto Shaman feels much stronger for Mythic +, but is literally only good for this type of content.

I think 4 Disc just won't have the DPS needed.
If your thinking about 5 hunters. I would consider leading with a Resto Shaman - it fills out the team so well. You can Target of Target your chain heals, and it bounces on all of the pets - keeping them alive + the hunter heal on them.