FormerlyHemlock
Hero
Well, a "warrior"-type naturally reaches a THAC0 of 1 at level 20, not counting any benefits from magic weapons, weapon proficiency/specialization (which I guess was optional?), or stats. And a THAC0 of 1 is where the problems start--it doesn't even need to be negative, because you cannot roll less than 1 on a die. Even if we assume a modest magic weapon (+2) and a 17 Str (not that unlikely), Warrior types can easily achieve that several levels before cap--and every other bonus ticks it down further (such as the Kensai Fighter kit). Get an exceptional Str, which was hardly exceptional in 2e's heyday as I understand it, and it gets pushed down even further--with sufficient gear and options, it can happen even before the "domain management" phase is supposed to kick in.
If you're fretting about a problem that happens only after you gain millions of XP over the course of a decade or more of play... you might be worrying about a non-issue.