I think MF model was a very big surprise for them
yes, Mf was a general improvement of Mig-21
Internal cannon, better avionics and better climb performances and acceleration
The Phantoms (expecially E version) remains much better as 360° plane but in a close combat at low and medium alt a good pilot can give bad surprises to F-4s pilots
Obviously in the hands of Israeli pilots, who knew how to exploit the best features of the Phantom, the F-4E was too much for the Mf
If you go only by Israeli sources, then what you say is true. The reality is commonly believed to be somewhat different.
The NVAF got the MFs in '72 (I think), and they were first encountered on 10 May. US intelligence knew about the possibility of MFs but did not know of the true asset they really possessed: increased thrust. The F-4s used to be B 'n Zers, but when they tried to outrun the MFs at low level, the MiGs slowly caught up and launched missiles. The surprise was great and aviators needed to reevaluate how they would defeat these improved interceptors.
the problem is: to what source believe
I personally find much more reliable data Israelis
1) the Arabs declared a number of victories but the same were never confirmed by scrap found on the ground or by guncamera (i can declare 50 Phantoms too but i had to show the pieces of enemy plane or show guncamera kill)
2) is much more difficult to hide losses in a democratic state that in the Arab states of the years 60/70
3) those aerial defeats generated deep reflections also in the Soviet
4) for what regards Vietnam, most of the Phantom losses where relate to the planes shot down by enemy fighters during ground attack missions over enemy fields. If we consider the pure fighter missions, the ratio would have been much more favorable for the F 4 (vietnamese makes only fighter, and in friendly territory!). This fact is very significant and should not be underestimated!
so, talking about planes, Mf was a good opponents for F-4 in certain areas of the flight invelopment, but is like compare an F-16 with an F-15......the last can do things that the first cannot and not vice versa
Bis version is very close as interceptor and slightly better in dogfight