I am a Quick Melee user exclusively. Ever since I was a noob and I saw a Distant Observer video explaining that the best combo is a Polearm Quick melee attack (i.e. combo-less/no stance) I was hooked. It clears the room faster than using stances and I have full control over both my actions and the enemies. Sure a combo can do an impressive hit, but that is just one hit. While you are twirling and dancing around with combos, I will have cleared the room and moved on already. Now maybe at the 200+ level enemies a combo would be better, but I have never found a reason to fight that high, so I am referring to level 150 and under enemies. (edit: Quick melee outperforms).
I have been testing melee weapons to find a replacement for my polearm once this goes live, and the best options I have found appear to be Sword weapons. Both the single blade swords and the sword/shield weapons seem to be pretty fluid (I think I had to remove the stance mod in some cases if I remember). I swear that DE once said on stream that "most users just use quick melee anyway", so if I am correct, it seems like this will be a big problem for them once the masses find out that Quick Melee is going away.