The B-10 is one of my favorite ugly, in between wars, airplane. It was quite modern when it first came out (stressed metal skin, retractable landing gear, enclosed cockpit and I believe variable pitch props). It did however, become obsolete very quickly. Take a look at the British designs of the same period to get an idea of how modern they were at the time.
The F-35 is probably not the airplane I would have dreamed off however it does not mean that it is not the right one for the job. Yes, it took fore ever, incredibly expensive and I would argue that the Air Force version should not have been made (the one with the smaller wings). Maybe it was a compromise to gain stealth. At any rate, the whole idea of BVR is to shoot down the opponent before the merge; you really want to avoid the dog fight if at all possible. Stealth does not make the plane invisible but harder to see which hopefully means you take the first shot before the opponent even knows you are there. The new version of the merge is that you and your buddies arrive to find no opponents around.
The British had the Tornado which did not have anywhere the capabilities of the F15 or 16 but by being clever they could wax a F-15. The latter variants of the F3 had a really good radar which was well integrated. There are stories of F111s knocking down F15s as well. There was an exercise in which F111 and Buccaneers were to attack shipping at low level. The F111s asked the Buccaneers to fly low enough to leave a wake and they would be following 15 miles behind. The F-15 CAP flying high saw the wakes and came barreling down to intercept the Buccaneers; they basically popped in front of the F111s who got 2 F15 kills that day. Also heard an F15 claim that F14s were easy kills; just keep an eye on the wing sweep and you could guess what they were about to do. The point is that the clever ones figure out how to use the tools they have.
If you look at the Ukraine there has been relatively little air combat and most of it happened at the start of the war. The reason is simple, both sides have good enough missile systems to keep the opponent at bay so you are limited to low level, get in and get out type scenarios. You have to keep in mind that the Russians have good ECM systems which they have used only to discovered that although it helped their aircraft get through it also affected their own defenses so it ended up being a double edge sword. This environment would be a great test for the F35 is you can find enough pilots with brass marbles to fly them. The problem is that we generally design equipment for the last war we fought, not the one we will fight in the future. I believe that the F-35 is trying to break ground in that respect.