Guys,
Perhaps these few thoughts could help.
I agree with LO that using the labels '5th Gen', '4.5 Gen' or whatever are not especially helpful. They're really a marketing tool to use with senior officer types, a sort of shorthand, and as ever with shorthand, the meaning can get lost in the translation.
Where I would gently depart from LO is the characterisation of the relationship between F-22 and F-35. Yes, both LM products - but one from Georgia, one from Fort Worth. That makes more difference than one might expect. And very different requirements. Taking the aspects as listed by LO,
Technology, yes, big pull through of stealth technology from F-22, but with major changes to address maintainability and the need for big moving panels and doors on a smaller aircraft. I was never 'read into' the details of LO signatures (even if I was I wouldn't be able to talk much about it) but what is open source is the fact that the F-35 has gone for a different balance between LO, aerodynamic performance and avionics capability, involving less aggressive targets for signature. Time will tell if it's a better balance. Airframe technology was very different to F-22, especially in choice of materials.
Design philosophy - F-22 was, in my view (please feel free to differ) the last of the 'ultimate' fighter projects, along with Typhoon, where the design was driven by very challenging aerodynamic performance requirements, including super cruise. These drove a large, twin engined design, dominated by two very powerful engines, big wings, and fuel. It's no surprise, therefore, that the F-22 weapons bays are relatively low volume - any design of that type will have severe restraints on internal space. It's also no secret that LM Fort Worth had decided some time back that the basic F-22 layout (side intakes, twin tails, blended wing/body) was the way forward for F-35, but with less aggressive air vehicle performance objectives. They may have been right - recent Russian and Chinese designs appear to have gone a similar way. Again, time will tell. F-35 is a more 'balanced design' than F-22, but the constraints of LO (restrictions on external pods as a solution to lack of internal space) still apply.
Avionics Architecture - this is one area where there are a number of significant differences in the way F-35 has gone about its business . The phrase 'it's not like legacy' (by which they meant F-22) was a constant refrain from LM avionics engineers. In particular, the software architecture is totally different, with the state aim of allowing easier downstream insertion of new technology. Upgradeability was a key target from the outset. Is it good enough? I don't know, and nobody else will until it gets into service. All i can say is that F-22 lessons were being heavily 'leveraged' (to use a 'yuk' US word) all the time in F-35 avionics design.
I suppose what i'm trying to put over is that any aircraft design is a response to requirements, and uses the best technology available at acceptable risk. F-35 is a full 20 years on from F-22, so it's not a surprise that it has used what worked on the Raptor, and used new stuff where it was available. It's a very different beast - time will tell if it ticks all the boxes.
Best Regards as ever to those who care about delivering the goods,
Engines