Blizzard has been using that term quite a bit lately, I worry for my enjoyment of the class once it's 'fantasy' is realigned, seems they are using that philosophy as the reasoning behind rearranging the guts of several classes.
Pve wise I am not too worried, there will always be a way to make the numbers you need to pull, its more so where warlocks will be in pvp after all the changes that worries me, having pvped through several expansions, when they gave us the toys in MoP (That they are now pruning away) we were so very durable, now it seems to me the more they cut, the closer we get to being significantly easier to kill.
Unless they devise a way that Melee wouldn't be such a threat, as it stands if you have someone on you and you cant shake them, there is no way you can go blow for blow and live. I suppose what I'm saying is, Blizzard wants to make us more durable to fit our fantasy, I argue that no matter how durable we are, if we can't get away from a melee player, especially with demon hunters coming, we are dead.