Realistically, what's left in the American lineup as far as combat aircraft are concerned? The primary US aircraft that have been wished for are the B-29 and A-26.
So let's think about it for a minute...
Regardless of how effective they'd be in any of the arenas, hangar queens or not, the list is surprisingly small. These are off the top of my head...so work with me here...
B-29 (coming)
A-26 (short list)
SB2C (which is already obsolete by CV-killing P-47s)
PB4Y-2 (which is basically just another heavy bomber)
P-61 (which lacks a definitive role)
PBY (which again lacks a definitive role)
TBD
SBC
PV-1
PV-2
C-46
C-54
From here, we get into obscure aircraft or variants of existing airframes, P-70, F-5, F-6. But even these lack definitive roles unless we get a night-fighting arena or the ability to make use of a recon or rescue aircraft.
The best idea we can come up with is to present a list of aircraft from all countries that can be considered 'must-have' gap-filling aircraft. Take for example, the Fiat G.55. Folks might say that we don't need another Italian fighter, but...the G.55 would be a step up from the 205 and would therefore bring Italian aircraft into parity with Allied aircraft for the average player.
The Ki-43 would be a nice addition, lightweight and maneuverable, but with serious handicaps in terms of firepower and pilot protection. We hear whines now about pilot wounds, imagine a Ki-43 in the LW arenas. The Ki-43 would fill a HUGE gap in the historical side of the game, AvA, FSO, etc.
I do heartily agree that there are deficiencies in the Russian planeset, especially in the attack aircraft and fighter areas, Yak-1, Yak-3, MiG-1, Mig-3, Tu-2, and Pe-8. Same can be said for the Italian plane set, G.55, Re.2005, Cr.42, Mc.200, Cant 1007, Br.42, SM.79, etc...
At this point, aside from some bombers (He-111, Do-17, Do-217, Ju-188, He-177) almost anything German that we add will be a novelty or lack a defined role. If we needed 40 troops to take a base then an Me-323 might not be a bad idea, but like anything else that's added, it's either uber or a huge target, so pick your poison.
As a group, instead of beatchin' at each other and flaming wishlist posts, perhaps we should establish a thread with a serious discussion of what's needed. The kind of thread that when read by someone from HTC, they actually get something worthwhile out of it instead of wasting their time talking about wanting nuclear submarines and space stations.
The problem with any thread like this - is that a few will contribute useful information, while others will bombard the thread with useless drivel that contributes nothing to the process. They jump on their particular aircraft bandwagon with total disregard to how the aircraft will operate in theatre. An He-111 will be great in AvA, FSO, etc., just like the Ki-43, but in the all-important LW arena they'll be chased down like goons by anyone with guns on board.
Truth be told, with the exception of a few missing fighters, Yak-3, Ki-44, J2M, G.55, etc., the list of aircraft that could operate in the LW arena (as long as LW continues to house the majority of players) is very small. There were a finite number of aircraft developed and built in that 7-year period. Eventually, we're going to run out of wishlist aircraft (I hope).