I actually kind of like THAC0 conceptually, and if the computer is doing all the math I don't have to worry about it.

I think it's just a UI issue where if you get an armor that's like, Chain Mail +1 the information screen will say that it gives you +1 to your AC, which would be bad if that were true, but when you equip it it actually correctly lowers your AC. So that stuff is a UI issue but I understand and can respect the underlying mechanics. Figure out you ac and thaco and then you just need to roll one die and check if it's over or under.

What I find less intuitive is when you're reading through spells and need to figure out what status effects you need. This gives me a +1 to save vs breath weapons bit for some reason that also includes fireball spells? Also wtf pretty much only dragons have breath weapons why is this a dedicated stat? Why didn't they make breath weapons use like... AoE saves or something? (I'm pulling this out of my head, not using a real example here)

It's very complicated and unintuitive. But that's OK, I actually really like the game and the system in general!