Are you saying you beat BG2 at 10 years old? Are you a russian chess grandmaster too?
Nope, I got to the Underdark in my first playthrough until I lost interest. I finished it when TOB got released and my dad bought it for me.
Despite me being very young, I distinctly remember the following :
- Struggling immensely at the start because I didn't know how immunities and magic weapons worked. Once I noticed some of my dudes were doing damage and some weren't, things started clicking.
- Thinking how 'cool' it was that the guy outside of D'Arnise keep tells you about fire and trolls, and that it actually worked like that.
- The umberhulks in D'Arnise keep wrecked my shit immensely.
- Umar Hills actually scaring the shit out of me. The ranger's diary was extremely scary and ominous.
- Vampires wrecking my shit immensely, every fight was a struggle to death.
- Feeling deeply betrayed by Yoshimo.
- My first character being an Elven Ranger.
THAC0 is a classic and integral part of D&D.
I don't think that TACH0 is overly complex, but simply picking the highest of 2 numbers (ATTACK VS AC) is way easier. If THAC0 had any other benefits or depth I'd maybe like it more, but as is it's just unintuitive for the sake of being unintuitive.