Ok, it's not too complex for Mr Wonderful but novice gamers will have trouble.
1) Obviously, non-developpers will have a problem with modding that requires developper knowledge. Who would have guessed.
2) The entire point is precisely that C# is simpler than C, while you promote C over C# on the grounds of complexity.
So your whole sarcasm is some sort of shooting yourself in the foot and you seem to have trouble not just with C# but with basic reading comprehension and logical thinking.
C# is based on C++, a complex language, which is based on OOP, a complex concept. "C" on the other hand is a procedural language, one step after another, simple.
Saying procedural is simpler than OOP is pretty simplistic to begin with. Like many things in software development, it might be a bit more complex to start, but it ends up making work vastly simpler. I don't even want to imagine how coding Bannerlord in procedural C would be.
Not to add that C# doesn't have to bother with memory management, pointers and other complex safety concerns that C had.
SQL is a simple procedural DB script language. (you don't need to know any programming language).
Yeah, because novice gamers won't have trouble with setting up a SQL server and dealing with SQL queries. That's just common novice gamer knowledge.
Mate, just be honest. You learned things in the past for which you got expertise and as such are simple for you, you can't be bothered to learn new things now and as such they are complex for you. That's fine. No problem here. I wouldn't be able nor willing to code anything in Assembly either.
But don't throw BS like "C# is too complex compared to C" or "XML is too complex compared to SQL" (like seriously ?) or implying that "novice gamers" would be able to deal with either modding in SQL or C. All that is just idiotically wrong.
Bannerlords has many faults, but the modding is not one of them, it's absolutely magnificent, and for the very reasons you complain about. Your preferences would make it ten times worse, no more accessible and vastly more limited.
In Bannerlord I can whip up Visual Studio, rewrite the code of any exposed method, make it a mod and change how the game is working.
In 20 mn I can change the damage formula to make armor count. In one hour, I can decide to give my Leadership skill the ability to give XP to my men each day.
Good luck doing this with SQL in a simpler manner.