So, let’s look at a list of things that we want from a z-level system:
Vertical structures in game, to make buildings feel larger without increasing their footprint.
The ability for players to build their own vertical structures.
The ability to fire from higher points on enemies below.
The ability to use higher points of elevation to see ones surroundings.
An architecture that can support flying enemies.
A meaningful climbing and traversal system, that allows the player to use the vertical to aid their approach to handling cities.
Enemies that can see you on higher locations and climb to your level.
Enemies that can hide on higher levels before jumping down on the character.
Multiple paths and manners in which a player can scale or descend structures.
Fire that can spread up and down a building in an interesting way.
Sections that collapse.
Well formed, easily extensible code.
These are, as far as I can see, the primary goals of a z-level system. How many of these does your solution actually meet? Just the first one? Because as you’ve already stated, we HAVE the basement system, which feels the same goal already. So what actual value does your system offer that makes up for issues it represents? (like stuff on different levels no longer being properly tracked, items that fall onto open space floating in the ‘air’, code that would need to be completely rewritten to implement any of the other goals…)
Basically, we’re not going to take the time to implement a half-assed hack that adds little of actual value, when what we want is a powerful, robust system that opens up a lot of potential. Your z-level mod is kind of nice thematically… but that’s it. It’s a hack that extends an already bad system. It’s not really something to get excited about, it’s certainly not an appropriate z-level system for the game moving forward, at most it’s a thematic stop-gap.
Also, seriously, your code can get kind of nightmare inducing. You’re obviously a smart enough dude, but some of it is REALLY bad, from what I’ve heard from those who went through the effort of getting it prepared to potentially port it over. >_>
Your refusal to use github certainly makes things like that more difficult to fix, since you leave yourself reliant on third parties to do all the integration and communication work for you.