I agree that planes should be "rotated" in TOD ... but ...
I don't like "scripting". As much as I've seen the FAQ and posts that hint at players having "less effect" on TOD's "war" ... I would like to see a strategic element added to the game where players can influence the logistics, research and development behind the scenes.
This could be done actively with the players pooling what was once used as individual perk points in classic into a point pool for the development of specific planes, tanks or other vehicles. Each player alloting their share to develop a specific piece of equipment.
Or this could be done in a more passive way, with the total pointcount on one side or the other determining when the next level of planes and vehicles become operational for their side.
In either case, I would like to see the industrial centers be an important factor as well - with a minimum amount of indusrty and research facilities having to remain unmolested for a minimum amount of time before new planes and vehicles are introduced. This sets a minimum time for one side or the other to "rotate up" but no maximum.
As you can see, it leaves the possibility for one side to introduce newer planes and vehicles before the other side does. Yet one more dimension added.
But ... hey ...