I think if we return to 4E I'll put a house rule in place that when a monster hits its bloodied value its gonna die very soon. Not sure what the rule would be, possibly if it gets x more hits or whatever.
See, I'm inclined to go the other direction. I'd tend to make monsters have more abilities or ways to recharge them so that they remain a threat up until the moment they're dead.
I don't yet have a Monster Manual so it's hard to for me to judge how much of the grind is built into the RAW but, again since I've heard the complaint often enough, I guess that it is. Since I didn't have a MM, I've mostly used monsters from free online adventures. But I've also had to improvise monsters where I had nothing similar.
One example was the Big Nasty Critter from the demo adventure I ran for my group in preparation of my campaign starting early next year. This creature was called a "Mist Mind" and was sort of like a big Grell with it's own flock of giant bats. The bats were Minions and had rather poor damage output but they were good at grappling. They'd swoop down and grab somebody and drop them into the giant mouth on top of the Mist Mind. Then it starts to chew on you. If it eats somebody entirely then it hatches a new bat. It also has a fairly damaging attack with its tentacles.
When I ran the combat with the Mist Mind, I knew that the PC's would have rescued some NPC's by that point and be trying to get them to safety. So this battle became one about the PC's trying to protect that NPC's from getting grabbed by the bats and dropped into the mouth of the Mist Mind, all the while trying not to become victims of it themselves. The Mist Mind managed to gobble up only one of the NPC's and hatch another bat. It nearly began chewing on one of the PC's (the Halfling Paladin) but another PC (the Eladrin Ranger) managed to Fey Step INTO its mouth and fetch him out of there.
Anyway, my point is that I think the players should never be left thinking, "Well this thing has used all it's nasty powers so we can just sit back and pick away at its hit points until it is dead." If this philosophy means that they burn through powers and Healing Surges faster and need to rest a bit more often to recover, that's fine by me. My campaigns tend in that direction anyway.