I fail to understand how 40 people fighting for 130 bases is interesting.
It's an economic scale. You want to do a hairy mission that needs 20 pilots? Ok, you need at LEAST 100 pilots online on your side to hopefully get a 20% participation. With 100, you'll be lucky to get 12 people join.
Honestly, the most people I've seen on even in US primetime is about 600 players (maybe spiking up to 700 briefly). That's 200 each side, for a few hours, if there's one server. Now multiply servers by 4.
50 players on each side and server, primetime, if things perfectly balance out. But they won't, because playing with 50 friendlies to try to take 130 bases against 50 enemies on your target bases is ... *yawn*. That's what happens on MA at 3am and it's time to log.
So they won't balance out. Everybody will pack into one of the 4 servers regularly within a few weeks, and the other 3 will be left to wither on the vine.
Sorry, but you can't take a player primetime base # of 600 players tops, and fragment it into 4 servers and still retain any sense of community and scale. About a week ago, I saw the Bishops launch a raid of at least 30 bombers (90 with wingmen), and it was the most glorious thing I'd ever seen. Certainly it took great coordination across several squads and even across alliances. That is history, unless everyone packs into one server again.
They will. And then you'll have only a handful of planes to choose from most of the time, instead of a regular ROTATION of time-period appropriate planes to choose from and learn.