There is a slight paradigm shift for 5e that is subtle yet profound. With bounded accuracy, and quicker combats, it is now more possible to create sessions that balance combat, interaction and exploration. As such, the R of RPG (roleplaying) becomes more important than just combat. When DM and groups take advantage of this balance, min/max has less of an impact on the total game. Sure, PC can wipe the floor with monsters in some encounters, but that does not guarantee that the same PCs will be able to interact successfully in non-combat encounters or find a way to get through a deadly trap, etc. 10 arrows fired at 1 PC is pretty dangerous. An undetected fire trap or cloud of poison gas, can be pretty deadly.
I'm finding that my players (and I, when I play) still feel tension even when we end encounters in 2-3 rounds even when we don't take damage from foes. The tension and fear comes from the uncertainty that the giant's club or the ettin's battle axe might hit and do 24 points of damage, or the dragon's breath that just injured half of the party might recharge and do it again. Sometimes this is enough to make the party plan ways to avoid combat if possible, or seek even quicker ways to end the combat, or even negotiate or try to intimidate to break morale of the foes.
I think the game is working as intended. (That said, most of my experience has been from levels 1-10 - I am hoping that it holds true from levels 10+ - Theoretically, if the R in RPG is understood, I think it will - plus, it is really easy to give monsters special abilities or spells to cast, extra AC or extra to hit bonuses).