WW1 arena is dead, fact a pair of planes won't make an arena.....
Korean Arena will be dead after one month, Saber vs Mig-15.
fill out an arena to see it actually thrive.
If the WW1 arena filled out plane sets, set up a few arenas (1916/17/18) you have yourself a plan.
1918 as a LWA, 1916 as an EWA..... however my best response would be to have separate perks for this..