The problem is there simply isn't enough interest to pay for the development and server costs.
Not to mention at best I never saw or heard of more than 50 people online with DOA.
Taking an admittedly wild guess. (personally I think the # of AH accounts is much bigger than this)
But being conservative, 6,000 people for AH, x 15$ a month = around 90,000 a month to pay the devs and support costs.
Even if it succeeded beyond our wildest dreams.
A WWII arena figure 500 accounts, would each have to kick in 180$ a month to reach the same level as AH.
In order to make it work you would need the same level of commitment!
In short, you would need to clone Hitech and his staff so one bunch could take care of AH, and the other bunch work on developing a WWI sim. Double the expenses, for nothing coming in.
There is simply no way.
The interest isn't there, there are not enough people willing to pay enough money to make it work.
Same is true of Korea era sim, although this would have a slightly larger fan base than WWI
I think we would be much better off long term to simply keep asking for early WWII biplanes that saw action.
Keep asking for spanish civil war planes. Keep expanding our already impressive plane set.
And if you really feel the need to go slow and shoot with popguns.
Drop into the TA and grab a D3a1 to get your fix.