The Mid War and Early War arenas are limited in plane options, and thus, few play there. In order to fill them more reliably, a new division of plane options should be put into place. The Early War Arena will remain unchanged, but the New Mid-War Arena planeset will be Current Midwar Planeset - Current Early War Planeset. The New Late War planeset will be Current LW Planeset- Current MW planeset.
If instituted, those who wish to fly midwar birds will fly in the midwar arena, those who love the EW will recieve the status quo, but the LW will be stripped of its hangar queens (Early Bf-110s, A-20s, P-51Bs, etc.). However, the MW will become more interesting due to its exclusive use of mid-set planes. The EW will become more interesting as well, since the early P-Series models will only be found there. This leads to the next point.
The LW arena has become overburdened by those who love mid and early war planes, but also enjoy some company. If instituted, they will move the the MW and EW Arenas, and the LW will flourish once again. When there are more than one or two people in the EW Arena, it will recover as well. Furthermore, more realistic plane matchups will be found- no more getting picked off by a higher model plane, but still being able to organize a horde *cough* mission.
Imagine the LW being used in its proper role, and the EW and MW erupting into the as-advertised 24/7 slugmatch that is Aces High. Imagine Mid-War birds being found in hordes, not as lost sheep. See the Wildcat zoom again through the mist, a Zeke hot on its tail! View the fruits of the R&D laborers in the LW, and see where it all began in the EW. All this, with a change of a planeset.

-Penguin