I say no to adding any aircraft for the world war one arena.
Here's why -
There is absolutely little interest in it, I missed the opening debute in which some say there were over 100 in the WW1 arena, the most I've ever seen was 5 on a friday night a few weeks ago, and even then 3 were AFK. Adding more planes isn't going to solve this - look at Early War, lately there's been a rash of early birds and no more interest then the usual perk farmers. If I want to play a WW1 game I play Rise of Flight.
I'd love to see AI pilots in the WW1 arena with a campaign for aces high - if real pilots join they get an appropriate spot in the flight and fly against possibly either AI or real pilots, Make it a campaign, with medals and rank.
Reason I say no is Aces high is a World War two game, Rise of flight is a World war one game - I much rather have Aces expand more plane sets, before committing to a project that has little interest right now. Maybe in the future.