The most important element Zomboid has going for it is simulationism and real world scale. Turning it into yet another cheap 'battle royale' would be a tragedy. The news about NPCs is a surprise, but I think NPCs will be good
within the framework that's already in place.
Having played quite a bit, mostly coop, since the big new update, I'd say there's easily enough to keep it interesting at least through the first winter. But you really need to play on 'apocalypse' and at least turn up the number of zombies or else the threat isn't enough to force you to constantly adapt and overcome, sleeping with one eye open (especially with more than one person, I personally use "high"). I also turn darkness to one step darker than default because otherwise night is essentially blue-filtered evening and you never have to respect the dark, use a flashlight, etc. The lighting is very good looking as well (rare these days), which you won't see if everything is washed out. The music, ambient sounds and general soundscape are top-quality. I find the atmosphere to be second-to-none for this type of game, and a reason to play it in-and-of itself.
At one point I found myself on an isolated forest road on the way back to town and rapidly running out of daylight. Luckily, I came to an auxiliary road with a weather station at the end of it where I could spend the night. I found a radio and turned it on before I went to sleep on the floor of a maintenance room. It was 0200 but one of the talk radio people was still on the air, talking about the bleak nature of death and how they were sorry it turned out this way, for everyone. In the morning all the radio stations had stopped broadcasting except for the Emergency Broadcast System.
Some time after that a friend and I were driving through farm country after packing everything up in a pickup truck to try and get to a better location in another town. After taking one too many beatings the engine started to die as we drove. At first you could coast along and start it back up for a minute, and then it finally went dead for good. We managed to stop next to the turnoff for a farmhouse, and decided to spend the night and figure out what to do. There was a rainstorm and the sun was going down, so naturally when I went inside the first thing I did was flip the lightswitch, and... nothing happened. The power had finally shut off, and the running water with it. Just then, in the distance, a woman screamed.
None of that being set-up or part of some story campaign is what made it so remarkable and what keeps the game fun, if that kind of thing is your cup of tea and you're patient.
I would recommend two mods in particular for what they add to the existing gameplay, though I use a few more and a couple things I made myself.
The first is the "
Expanded Helicopter Events" mod that turns what is by default a single flyover by a helicopter and turns it into a half-dozen different types of helicopters, airdrops, crash sites, and jet flybys. You can also set them to cease after ~90 days or continue after that point, though they become more hostile over time.
The second is "
Save Our Station" which adds a weather station to each town along with a nearby location or two. Very professional quality, but the real addition is that with (a lot of) time the Emergency Broadcast System will no longer broadcast in your area due to a failure in one of the relays. These weather stations are those relays for that system, so you'll need to find out which one is failing and go repair it if you want to continue to benefit from the information it provides (which includes air activity). It gives you another thing to do later in the game when you might be looking for reasons to have to wander from any base you might have built.