The reason they didn't work out as daytime fighters was that they were light bombers. Trying to use twin engine light bombers as fighters against single engine fighters was never going to end well for the twin engine plane no matter how many guns you stuffed in the old bomb bay.
They were both heavy fighters and bombers - like a lot of fighters were effectively by that time of the war (albeit granted not that many with internal bomb bays - but you did have the mosquito). With the extra speed though they were supposed to take back the Zerstorer role from the Bf 110, but that never really happened. Being able to use them to attack B-17s and B-24s, with an escort, gave these designs a new life that made them useful again.
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Great photo by the way.
Yes it had two 13mm guns firing to the rear but only in rarest of circumstances were you ever going to get both guns to fire at the same target at the same time.
About the only thing you can say for it is that the gunner didn't have to fight the windstream to aim the guns as it was power operated.
Apparently the remote control worked though and even one 13mm gun, so long as it doesn't jam, is pretty daunting for a pursuing fighter.
I am sorry but in many cases you examples of "obsolete" aircraft don't actually work the way you seem to think.
Bf 110, Ju 88, Do 217 were definitely obsolete for daytime combat by 1944, and they were vulnerable to Mosquitoes at night. To me that is obsolete or pretty close to it. My whole point was that obsolete is a matter of degrees not really an absolute. At least until you get to the "target tug" role.
The main JU-88 used in the BoB was the Ju 88A-1 with some help from the A-5. The Germans never made things simple, right after the BoB the main production was switched to the Ju
(snip)
You may have read an awful lot about the operational history of many of these aircraft ( I would say more than I do) but you seem to lacking in detail knowledge about the actual performance or armament of some of these planes. This makes reaching valid conclusions about the general course of development a bit difficult.
I readily admit I don't know about all planes in the war, like most people around this fourm I basically know more about the planes that interest me. That said, lets not make a mountain out of a mole hill. I knew there were fighter armed Ju 88 variants, I just thought those were used as night fighters and in the bomber destroyer role. I was never frankly interested enough in the Ju 88 to put together the aggressive maritime raids with the heavy fighter variants.
We all have our little areas of expertise, you know the engines very well as I have conceded before. I know a few types inside and out, I daresay I introduced a few things about the P-40 both operationally and developmentally that were not widely known around here. I may do so with a few other types like some of the Russian fighters, if I have the time. I do tend to focus more on the operational history and work my way back to developmental details from there, because that way you can avoid all the dead-ends and clutter that didn't actually go anywhere.
But ultimately you need to cover both sides of the equation, otherwise you'll have a distorted understanding of the subject.
My actual historical field is another era entirely, and there is an interesting analogue in legal history. They used to think that in this era if you did X you would receive punishment Y, plain and simple, because that is what the law books said. For decades this was what was said about the period, punishments included a lot of Y meaning very harsh things. Then somebody started looking at the actual court records of actual cases. Aggregating dozens of them. And a different picture emerges. Turns out the real world punishment was not what the law required but was instead typically a much milder "A, B" or "C".
I think you can draw a similar comparison to WW2 Aircraft. If I looked at the Curtiss Helldiver on paper I might assume it was a great bomber. Almost 300 mph speed with a 1,900 hp engine, two 20mm cannons plus 2 defensive machine guns, 2,000 bomb load for dive bombing or a torpedo, 1,100 mile range. It looks pretty good. Only by reading operational history and pilot reports do you find out what a dud it really was, at least in the early days (and I'm not sure they ever really fixed it).
So I do think you have to look at planes from a few different angles.