I think that you've demonstrated that you don't know what THAC0 was because you are light years away from talking about what thac0 actually was.Because its one of those things where you, as game designer, grok it so fundamentally it doesn't occur to you that its confusing as hell to a typical customer that hasn't already spent the time grasping the concept.
Put another way, its a mechanic that emphasizes system mastery but in a very negative way; mastery isn't desired because thats how you reach a higher level of play, but because the system is ridiculously confusing and you need that mastery just to play.
Thac0 was not the ascending/descending ac. It started from GM's trying to put pertinent info on the character sheet for pregens at con games. On the character sheet you had a THAC0 box for each weapon
- [d20 roll] -> Player
line on sheet
-> [player says number above the box for that roll] & the game continues on
insteadthat has been "simplified" to the current:
- [d20 roll]->player:"uhh 16 plus 5 from [attrib] [GM:"that's a hit"]plus prof bonus of... umm.. gotta find it... [GM:"that's a hit"] 4 for
um[GM:"that's a hit"] twentythree [GM:"that's a hit"] oh plus one for my weapon[GM:"that's STILL a hit.. I SAID IT'S AHIT, YOU HIT"]does a twenty four hit?"[GM:"yes that's still a hit"]