For what it's worth, I think this is the best Alpha I've played (and I've been around since A8). I haven't had this much fun with 7DTD since, I dunno, A15 or A14.
I really like the concept of sleepers, but having one appear in nearly every closet, or up in the rafters / false ceilings, is really gamey. Like, how did they get up there? It simply ceases to be a surprise once you've gone through the same POI a handful of times.
I too would like to see way more zombies outside. In my perfect 7DTD world, I'd like more variety. In some towns, most of the zeds are outside. In others, most might be inside. Some towns will feature a combination of both. Some towns will be nearly zed free, while others might be swarmed with zeds. There's so many ways to mix & match things (well, in theory).
Still though, I have to tip my hat to TFP. A18 is really a blast. I've been having so much fun with it as of late.