If your problem is too many good players in a tier, you are looking at it in the wrong way. Believe me, you will thank for T3 being still played by the vets, as in times, where vets were mainly moving on, the quality of games plummeted. It is bad if you learn a certain behaviour, which is just bad for gameplay, and don’t realize it, keep repeating it. And I speak from experience, not to talk down; I have a habit of picking up stupid habits.
I was a long, looong time in T3, back in the days where experimental was, as residente said, something you just put on, because you had it. T3 was full of veterans when i entered the game. It was almost harder to find non-veteran players. Everybody seemed to at least know how to kill and fly. This made it very easy to learn. After just a few games, I could fly after other players, and realize what they were doing. I watched the stats of single ships which had been assembled, just to find out, how I could improve on ships, which seemed to work well for others, but not for me.
I play T5 aswell, and I can say, there are a lot in T5, who should at least spend a couple more months in T3 actually. If you see engineers in T5 cycling their heals to heal you, or still people equipping a lineup of 2 LRF and nothing more, you know, this is not the endgame content you were hoping for. I cannot imagine, how they grinded their way up, with those tactics; but I am a very slow grinder anyway, so sometimes it blows me away which amounts of work people put into things, even if they end up not understanding what they are doing. I tried every role in T3 first; I think I even flew every single T3 ship, and gave every T3 ship at least a chance to show what it’s worth once it fully synergized, and sometimes came back to them if i realized that i had not seen a specific strength of a ship before. It was easy to complete the tier, and T3s continued to support me as I started building my first T4 and T5 ships. As I entered T5, I already had a couple of ships to rely on, because I simply knew which fit they are going to use, and I knew the cousins in lower tiers. With that, T4 and T5 took me really almost no effort.
It is true, that multi-ship-talents are more rare, but do not assume, a pilot which seems to use a certain type of ship more, because he excels in its playstyle, has no idea how to fly the others. Even if you are bad in a ship, learning how to deal with its weaknesses gives you a great insight in how to actually defeat them. In T3 any ships weakspots are usually obvious.
Of course the modules make a difference, but especially in T3, getting to fully purple on one or two ships is really not a big deal.
If you have the grind nerve, you could also do a lot of PvE to get the ships synergized, does not mean however, it isn’t bad to actually use those ships, since it isn’t just about “unlocking all ships”, it is actually about the game you play with them.