It is worth remembering that many of us have played the game for hundreds or thousands of hours and already sucked the marrow out of these POIs in the process. Even if drop zombies and monster closets were all but eliminated, long time players could still reach a point where the POIs are ‘stale’ because they know all the places the zombies can spawn.
It would be possible to address that staleness - the predictability, lack of surprise, variety, replayability, whatever you want to call it - even under the existing system. Namely, the level designer can put in more zombie spawns than are actually used in any given playthrough. A room that only needs three zombies could have a sleeper volume with twenty different possible sleeper spawns. The standard the level designers actually use, last time I checked, is to only have one more spawn point than the minimum needed. So a room with three zombies will have four possible sleeper spawns.
The downside of course is it’s a little more work to add more, and the zombies could by random chance be clustered in one spot in a way that’s undesirable for gameplay. But it’s less work compared to adding the wandering sleepers or bandits I mentioned, or trying to satisfy our appetite with ever more, new POIs. I guess what I’m saying is, sure I want all the fruit, while also recognizing some of it is lower hanging than others.