As I see it, the problem with EW, and to a lesser extent MW, is that there's nothing unique about them. Everything that can be found in EW and MW is also available in LW and that's why everyone gravitates there.
It's really no surprise that EW is a ghost town given that it has the smallest plane/GV set. As those sets expand in MW so does the player base and, as it expands further in LW the player base expands exponentially.
The only way the EW and MW arenas will gain more poulation is if they each offer something unique. WWI will likely gain a small but dedicated following as what's available there will only be available there.
The AvA does offer something unique in it's plane sets, maps and structure but I think the changing periods, plane sets, etc. confuse and put off much of the player base as you don't really know what you're going to find when you log in.
I like the idea of theater specific arenas (east front, west front and Pacific) but actually think this idea should be applied via the AvA concept with set maps (maybe seasonally adjusted) and plane-sets so you always know what you're going to find. If these began to gain a following they might be further defined into time periods.
That still leaves us with a dead EW and a moderately thriving MW. If people are dead set against limiting plane/GV sets, then maps and/or gameplay are the only options for differentiation. I don't think maps alone would do it, therefore a fundamentally revised type of gameplay would be the only remaining opportunity to differentiate these arenas.
I think that 50-100 people each in smaller communities (arenas) would be healthier for the game than packing 800 onto a big map (or worse yet a small map) and watching the hoards roll. People might actually get to know each other again. Squads might roam from arena to arena. I'm not saying get rid of Titanic Tuesday... I'd like to see it kept as a unique event.
I'd really like to hear ideas on what could be done.