I think you'll be pleasantly surprised once the third-party scene takes off for the new series.
After all, we had plenty of early-war birds turn up after the initial release even for Il-2, the Gladiator, for example, even if it was created as an export version. Lots of guys from European countries other than England and Germany have an interest in the earlier types because they were the main types in use in their countries. The Buffalo for Finland, for example.
BTW, I think one of the guys earlier in the thread had it nailed when he pointed out that give the screenshots we've seen of the armament screen and the info that many have given regarding the profusion of different variations of the cockpit/head armour styles among all three models, equipping any aircraft as an E-4 instead of an E-3 will likely be more of a case of choosing the belting. Admittedly that creates the "inaccuracy" of being able to fire older-type ammo with the newer MG FF/M, but given that on choosing the ammo you're semantically choosing the gun it's loaded into, and in terms of the damage model and aircraft weights there ought not to be a noticeable difference in the MG FF -> MG FF/M transition so I don't think it really matters.
The real omission is the E-1.