I have a Supernait 1 and to me too it takes an Hicap to make it rock and sign properly.
Without the Hicap, the bass was slow, midrange laidback and treble not super neat. All of these disappeared when I added the Hicap and it also went deeper on lower bass notes as a bonus.
I never gave a listen to a Supernait 2 or 3 as I don’t feel the need since I added the Hicap.
You need to know I have the followings in another sound system and I appreciate it to the point I may even prefer it to my Supernait/Hicap :
NAC 32.5 with Neil Jadman’s cards/CB Hicap with Avondale TPR4/NAP 160 BD in its original and freshly recapped form.
Knowing what I know now and given the ease of repair of the vintage Naim gears, if I was you, I would install after market cards in your 72, add an upgraded Hicap and recap the 250.
From all the Naim products ever made, the 72 is a star when modified with a better regulator and still beats many contemporary preamps IMO.
Oh, and I also have an original NAP 110 that I connect to my second sound system when I come back from a live rock show to refresh my memory as to how a dynamic and live sound is all about !