The article I posted from Bill Paley is fairly typical of some of the things I've found in the early run of Alarums & Excursions: it reflects the complexity and assumptions of the early years of RPGs in a way that I think gets lost when we just look back at the official products and the reminisces of the TSR old-timers.
I love the fact that Arneson let the players roll for level. But there's an element I want to point out that I think goes a bit deeper. In A&E, and throughout its early years that I've been reading this is consistent, a DM (referee) was a person who had a "dungeon." GenCon games weren't scenarios prepared with pregen characters made up for balance; they were forays into an existing dungeon, at least until TSR started releasing tournament modules and that became the basis of the whole format.
Both the PC group and the monster groups were simply massive. The PCs (there were upward of 12) run into 50 orcs. I guess the "# Appearing" column was read literally in some of the larger games. It's interesting to see in context, because decades in which 12 is an almost unmanageable number of players has created the expectation of much smaller enemy groups.
What's probably the most fascinating is the fact of wildly contrasting play style and expectations. Bill's "heretical" assumption about 1st level magic-users is interesting by contrast to the idea thrummed into my head, and probably countless others, that a first level MU is a sleep spell, or maybe a magic missile, and nothing else. The three little books, plus supplements (which earned quick and widespread use, but mixed approval) created a riotous diversity. And for what it's worth, I think that's something the modern old-school gaming scene needs to nurture and expand.