Personally, I just want something to do in a server if there are few or no people on at the time. Constructing gorey scenes has its qwerks, but it doesn't even come close something like minecraft ... not that it should. Waiting around for even 30 minutes for someone to show up is beyond boring, and you know it. I need something to do there.

This is why I suggested AI. At least I'd get some practice against bots, or heck I'd even modify the bots if the method to isn't too complicated. I would at least ask for an apocalyptic scenario with super-simple AI (player in range -> run, jump, hit with over-sized shovel; player not in range -> wander aimlessly and randomly). This can be anything with that simple AI, from zombies, to dinosaurs, to aliens, to giants, to whatever! I would play for hours on end, especially if they had the equivalent of giant shovels, so if they spot you, you can only hide deep, as the AI would be set to keep attacking in the set direction for 1 minute after last spotting an enemy. Zombies alone is literally undeniably one of the most popular genres around at this time. It's hard to go wrong with zombies. You can even give AI soldiers only lots of grenades, or make a unique really inaccurate gun, and "AI Gun" (that no player would sanely use).

I know you said that it would be messed up by future updates, but will there be that many future updates at this rate? Just make a simple AI and change it when you need to. You need to adapt to the current state of things. Please just try it.

Are you missing models? Tell me and I'll make them. I was making a T-Rex just the other day, but the detail seemed low, so I kept making it larger. The model can be scaled by the engine can't it?