I understand the ability to do this would be highly dependent on the actual program and how the code is written. Know having said that… What about putting a minimum fleet requirement on Tier access.
T4 Fleet 30+ or you can’t access T4 PvP/PvE. For T5 say Fleet 50.
The changes to the MM have been very positive for reducing wait times. Unfortunately people rushing Tiers completely clueless as to what they are doing is taking away from gameplay. I just think this may be a way to balance things out without you devs having to render almost useless some of our favorite builds and weapons.
In my opinion T5 should be something earned not just purchased with a handful of DLCs If you can lock most of us out of T1 there must be a way to lock fleet 3s out of T5.
This game requires rushing hier tier ships for efficency.
You only unlock the good contracts for T3 if you have T4 ships.
Vice versa for T4/T5.
Also there is the rank 15 Crew Implant which further encourages Tier rushing.
So before you implement a stupid barrier, maybe it would be reasonable to change these mechanics.
Also that people still could buy their way into T4/T5 by buying all T1 GS ships is a major flaw of your idea.
On a sidenote, my fleet strength is 26 and i can play T4 competently. I still prefer to play T3, when i am playing solo, because i only have 2 well equipped T4 ships. However i would really dislike anyone forcing me to grind out synergy on low tier ships just to be able to occasionally play T4 with friends.
A more reasonable limitation:
You can only solo queue for T4/T5 PVP, if you have at least 2 different ship types of the respective tier.