I thought about a 5th platoon, but three things kept me from doing so:
1, I thought it was getting a little on the cumbersome side, and the more vehicles the more of a tail the notational higher level unit needs.
2, I always liked the 3 line platoon, 1 weapons platoon format that the Wehrmacht used in the second world war - and occasionally you would find a pair of morts in the HQ section.
3, But most importantly, we have some limits on what we could do: No upper limits on spending - yet - but the manpower limits are in the 150-250 men range, so had to take that into account.
I based it off of the current ACR troop, but instead of straight up Cav, I flexed towards Mounted Rifle, sort of a primarily recce, but with the manpower to do line if needs be. Hence the larger number of not only dismounts, but IFV's as well. I went with 3 squads of 2 sections to keep manpower down, while making sure that the vehicles can actually carry them and their equipment easily.
I seriously considered doing the APC/IFV mix: And I might do so if the group puts a spending limit on us, I figure for most uses, a OWS is good enough. If the platoon is mixed APC/IFV, or if 3rd is a 'shock' platoon with IFV's and the first two with APC's is still up in the air. I am leaning to shock just for the coolness factor of it.