demi-human racial level limits and it intrigued me so much I started a thread on Dragonsfoot about it. Level limits are a hot topic in old school D&D because it's one of those areas where players that often seek to be purists about cleaving to the "old ways" often diverge from the way things were. In other words they always have a justification about trashing level limits. And of course new school gamers, unhindered by or ignorant of the past rarely consider such rules good or rational. The fact is they were quite rational as Thoth's article clearly points out.
The reason I bring it up now is that I too find myself considering the race as class limitations in light of the rule innovations in the Adventurer Conqueror King System. It's actually a novel approach to keeping the unique quality of the demi-human races while not "restricting them" as much as creating them as a separate class--no pun intended. For they do indeed have classes all their own, that humans are not allowed access to. A cool approach, and though I don't feel the need to justify the rule concept, find answers quite nicely the objections of detractors.