A quick look at some numbers. Assuming that these are the "most popular" ASL scenarios given the number of recorded plays, we find:
Code:
Average Number of Attacking Squads: 11.8
Average Number of Defending Squads: 9.7
Average Number of Attacking AFVs*: 3.7
Average Number of Defending AFVs*: 1.7
Average Number of Boards used: 1.7
Average Number of Overlays used: 0.2
Average Game Length: 6.5 Turns
* (only when AFVs are present on at least one side)
Number of maps doesn't include partial maps or distinguish between the "double-wide" and regular maps. In one case, an HASL map is used.
Longest scenario on the list is 9 turns. The majority are 6 turns. Shortest is 4.5 turns. There are just three with a turn length >8, and all three come from the first two ASL modules (BV and Paratrooper).
15 of the 34 scenarios have no AFVs at all (in other words, infantry only).
Only one scenario has no infantry (AFVs only).
Largest number of AFVs present in a single scenario is 12, also the scenario with the largest number of AFVs for a single side (9).
Largest number of squads on a side is 19.5.
Average number of squads for both sides together is 21.5
Highest total number of squads for both sides is 50, lowest is 13 (not counting AFV only scenario).
It would be hard to read too much into the force ratios, which are all over the place, given the number of variables a scenario designer can make use of (leadership, SW, ELR, etc.) and different types of VC.
But perhaps worthy of note that overlays are only used in four of the 34 scenarios (4 overlays in one, and 2, 1, and 1 in the others). I don't see any Desert scenarios on the list.