From my perspective the Americans, Japanese, Russians and even Italians totally dominated the germans in "2nd generation" airframes.
Not really in agreement here. Fw190D9, Me262 and Ta152 prototypes flew during 1942. The Me262 was not ready for service until 1944 because the engines simply could not be developed much earlier than that, but the Dora and Ta series were ready for a "go ahead" since early 1943. That they were not given a green light had more to do with german fixation into turbocharged engines and the particular dislike of Tank of the Ju213 powerplant for the 190 evolutions.
Germans spent all late '42 and all 1943 looking for a turbocharged 190 and fighting to make the me209 and me309 worthy fighters, yet the D9 and Ta could've been flying since mid-43 at the latest. I'd say both were excellent airframes.
The 109 was saddled with all its major shortcomings thruout the war. While the 190 was clearly a better plane in many ways it never really was a dominant air to air weapon with most expertain favoring the 109 by a wide margin.
This is a higly subjective question. Most of the former 109 experten who flew the 190 preferred the latter. Some (a small number) liked the 109 over the 190. Depends on who you ask, and the context the pilots where flying at. If I were a german pilot flying Reich Defence during 1944, I'd rather like the 109 much more because of the altitudes the fights were being fought at were well over the ones the 190A was effective, but where the 109s still performed well.
If you ask the pilots in the 1942-43 channel air battles, or those in the russian front who flew both the 109 and the 190 there's almost general consensus (there are some notable exceptions but most jagdflieger loved it) the 190 was a better fighter than the 109.
It's hardly accurate to say that "most experten" favored the 109 over the 190 when probably the most respected of them all, Adolf Galland, who did 90% of his air to air kills aboard Bf109s, asked for all the Bf109 production to be brought to a halt, and for the Fw190 to be the standard propeller engined fighter of the Luftwaffe.
The 262 certainly was the true 3rd generation airframe and was well ahead of its counterparts...at the same time the lack of better plane was a serious issue by the end of 1942. The gravity of the problem is clearly illustrated by the luftwaffe's attempts to "force" the G.55 into german production (which I feel would have significantly altered the course of the airwar and more then likely significantly impacted US daylight bombing)...
I honestly don't see where the G.55 could've played such a decisive role. It was a good fighter, I agree, but the place where the LW was being slowly but steadily attrited were the air to air fights against the bomber raids on the Reich. At 25-30000 feet I can't see how the G.55 would do a better job than the Bf109s then in place. In fact I think neither the germans or the italians had a plane with better enough performance over the Bf109 to justify the latter's replacement.
The main problem the germans had since 1943 had more to do with where the battles were being fought, than with the planes themselves. At the eastern front the fights were almost always under 6000m. Over the Reich the fights happened between 7 and 9km of altitude. In the East the Luftwaffe had to fight at low altitudes. In the West they had to give battle at very high altitudes.
The germans had to make do with two different fighters which could fight at any altitude from down low up to 10km of altitudes, and that was something really difficult to achieve, even more if we take in account than in the East they were fighting hordes of planes specialized at low altitude fighting, while in the west they had to stop the tide of a high-altitude specialized fighter force. Building fighters able to fight in both scenarios was something the germans were forced to do...but the fighters themselfs couldn't excell at every altitude they had to fight at.
When the Ta152H entered service the LW finally had a high altitude dedicated fighter which was still able to provide sterling service at low altitudes aswell . But that was already way too late. Had the Ta152H entered service by mid-late 1943 (and there was no real reason why this could not happen other than Tank's dislike of the engine, and the RLM insistence on turbos over mechanical superchargers) things could've ,this time yes, been very different from what they were, for it was a much better fighter for the altitudes we're talking about than the standard 190s, the Bf109s and the G.55s you mentioned. The 190D9 could've given the Fw190 family a better shot at the altitudes usual in the west (even though it was not an specialized high altitude fighter). It could also have been built by mid 1943 but it didn't enter service until late'44. The reasons?...ask the RLM...wrong decissions.
All in all I don't think the germans had a problem with airframes, nor engines. The airframes were there. The powerplants, too (The Jumo213E was already around by early 1943. The DB603 series ,too, tho this had problems with low production and the Reich's completely misguided police of using them in bombers before using them on day fighters). What was lacking was a good guidance from the higher levels where decisions were made, a guidance which took all the incorrect decisions possible in the 1941-1944 time frame.
