The scripts are saved in binary, unreadable text files. The script editor parses the files into something readable and gives tools for editing the scripts, but it's buggy and doesn't allow for new scripts with variables.
Ah, I just tried to open one of the script files and figured the same

I never figured script files had to be that complex... scripting for our game will be done in plain text...
Maybe we're working off a different definition of game engine. The game engine to me means everything that makes the game work and display properly; they're the parts of the game that govern the interface, graphics rendering, file loading and saving, and etc... With the game engine established and working, it's easy to add places to the city, make changes to the game logic, and so on. In my current build of my patch, I've made changes to the code of nearly every job function, and will be making more such changes in the next stage of my development of the mod... which will start once I finally get some random girls to release with the current download. I've made modifications to what does and does not display on the main screen, and made changes to the game logic that determines how many customers the brothel gets and where they are inclined to go. One big change I'll be making is removing the ability to enslave unwilling girls (though you could still torture her into submission...) This is all not part of the game engine, not part of what makes the game tick.
True enough... I am not a programmer and I got into that so I could make a mod for the original WM. As I was half way through my first book on C++ (I did some coding but it was a really long time ago) some guys started a WM project on Python and after I saw a few lines of the language, I fell in love with it
It's an interesting experience for me to see a game made from scratch and maybe I got the engine part wrong cause we already have an engine that can display info and make screens and do some kickass manipulations with images... and saves + loads the game.
So I figured a game engine is what our programmer been coding so far: classes and functions that extract data from .ini/.xlm/.txt files, sort it and create objects with that data, giving us access, ability to mod that data, set flags and so on(that data is everything from girls, to items, npcs, hero and other ingame heroes,work, rooms etc.)... now that I think of it, your definition is prolly closer to Game Engine than mine...
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With the game engine established and working, it's easy to add places to the city, make changes to the game logic, and so on.
Here is my confusion: this thread was started by some seemingly professional programmers, why is their first instinct to create a similar game in the same programming language?
I am well aware that it is not that difficult to add an empty screen or modify functions that are responsible for game's logic and mechanics. But it IS pretty difficult to create (for example) an arena in that new window where you can have your slaves fight monsters or other girls you don't own. It is also not easy to create graphical representations of those 'logical' areas where you win businesses from other gangs or make other very obvious improvement to the game like adding Quests and NPCs.
Most an average coder could hope to accomplish is create a clone of WM that has a slightly different approach to how jobs affect girls's stats and how girl responds to players 'ingame' requests. Maybe a couple of scripts to improve interactions or even make a new skin for the game. Someone who feels like he is able to create game like this anew should be able to improve on WM greatly...
PS: If you could ensure that after you preform an interaction with a girl on girl_details_screen a corresponding image is displayed instead of 'profile' pic when you release your mod, it would be great. It is one of those functions that nobody should be against and clearly improves the gameplay...