If we look at current game, we sometimes find ourselves in battles where one team have pretty much won from the start due to the tanks they selected in the garage (50B against Obj 279e/Vz55 for example, especially in a T8 game).
This also makes it so only a few different tanks are played at T8. So despite being a tier with a huge amount of tanks, only a few selected are played (Skoda, Progetto, Bourrasque are main offenders) because these are the tanks that it is easiest to win with. While other tanks pretty much never gets seen on the battle field (Schwarz Panzer, Mutz, Panther 8.8, Panther II, Hwk12, Centurion 1, KV-5, T-34-2 etc).
So how could we change matchmaker to create a higher diversity of tanks picked in the game?
I suggest following. We remove the current template based system, and instead use a tank weight system where each tank is given its own weight, and depending on its result (wins and losses) over the last day, this weight increase or decrease appropriately.
Then the matchmaker create teams based in tank weight such that both teams have a similar combined tank weight, and that highest tank weight tank on both teams are similar and lowest tank weight tank on both teams are similar.
In this way, tanks that lose more then win will get a lower tank weight and thus get seen as a weaker tank by matchmaker, while winning tanks will get seen as a stronger tank. Result is that you can now pick a weak tank, and the matchmaker will not punish you for picking a T7.5 tank like Panther 8.8 instead of a T9 tank like Bourrasque.
Source: https://www.reddit.com/r/WorldofTanks/comments/s9itf2/proposal_to_a_fairer_matchmaking/