Anyway, modding is a form of art, as it manipulates perception and emotions. Therefore it is not easy to explain to a layman sometimes. Sorry if it sounds haughty, but I've been in this business for over a decade and it's just how it is.
Just want to add, that this is not the only definition or interpretation of modding.
It's perfectly valid, just not the only one.
For me, modding is nothing of above... and certainly not an art!
Modding for me is adding variety (so that base game doesn't get boring/repetitive); and maybe adding some challenge, so that it doesn't get too easy. And everything and anything added must have a real tangible purpose, no fu*king poetry.
I explicitly don't want mods to manipulate my perception and/or emotions; and if they do, I try to do everything to ignore it. I also absolutely hate it, when mods add things, which don't serve any "real purpose"... e.g. needing an aquarium for captured fish, instead of just using a perfectly fine alien containment (if it's versatile enough for aliens, I'm sure we can put a little water in it too)... drives me mad. Just like I find "modern art" a waste of human potential, I find such features in mods a deliberate and targeted waste of my time. Adding things like that should be a modding-crime.
This post is intentionally harsh, but I needed to say it that way.
Please don't be offended, it's nothing personal.
Because it is bad design.
I don't mind people hacking saves or making cheat modes, it's their life and their entertainment. There are ways to draw fun from this. But as a developer of a mod meant for other people I can't do this stuff, because it's unprofessional.
Also please consider that there are many players who will do anything within their rights to win; anything that is not specifically forbidden is fair game to them. Then they come and complain that the game is too easy (or worse - brag how unstoppable they are). What am I supposed to do, make the game impossibly hard to give these people a challenge and make it hell for everyone else? Nah. But if I let them be, other players will feel like suckers, because their soldiers will be weaker, their bases will be smaller, etc. So leaving such exploits actually promotes playing dirty and ruthless micromanaging, which is a very bad thing in itself.
By that logic the original xcom would be the worst game in history.
Yet, it's one of the best!