I'm running several Teams.
True that I should focus on one, max two but well, I like the changes in gameplay from team to team.

Only played M+ in season 2.

My best so far:
5 BM Hunters - M+7
Trinity - M+6
5 Druids (Bear+3Boom+Resto) - M+6
5 Protec Paladins - M+6
ProtecWarrior+3ElemShaman+RestoShaman - M+4
4DemonWarlock+Holy Priest - M+4

Sometimes I change and mix, I have a spare 5th warlock, 1 Holy Paladin and a Frost Mage.

Strangely enough, most of these best dungeons were this week, with the awful sanguine and fortified combo...
Sanguine is by far the worst...

Difficulty of dungeons (from easy to hard):
Waycrest Manor
Motherlode
Freehold
Tol Dagor
Temple of Sethraliss
Shrine of the Storm (in fact, last boss is extremely easy with 5 hunter and 5 protec)
King's Rest
Underrot (because of 3rd Bosse, didn't yet got the right strat)
Siege of Boralus (I don't even bother doing the last boss, so I avoid it)
Atal'Dazar (Totem Poison Boss is a nightmare - well, mostly the killing the totems part in fact)

I have some videos but the editing part requires lots of time (since I'm not used to it).
Since last week, I'm capturing all my runs to learn with them afterwards.
It's working