Don't forget its still in beta and according to the devs, tweaks to the mm system are coming. Right now technical issues are getting fixed.
A more systematical issue with the mm system occurs when players who have TIV in their fleets and don't play them because they want to level their TIIIs. As long as these players don't put their TIVs out of their vet fleet, how should the matchmaker know they do not intend to play them? According to the hot topics mm takes the fleet composition in account, so when you have TIVs in your fleet you get equal opponents. So the player rank is a better determinator of good/bad mm than the ship tier.
To avoid this issue, I put only TIIIs in my vet fleet when i want to level my Otranto (TIII Med. Destroyer) for example. Another positive side effect is that maintenance cost is way lower without TIVs. (900 instead of 1500 credits)
Same thing with recruit fleets, as long as there is one T1 in the fleet, the whole fleet value is <TII and you should not be put in a vet game with your recruit fleet.