WG just released battlepass video, go check it out if you did not yet.
Every other publisher, game where is battle pass allows to grind currency it was worth back. And guess what, WoT does not allow to grind back gold you spent to buy improved version for next season.
Guessing by them not saying about aplying same improvement for any upcoming seasons. They just want to milk player base as much as possible by forcing them to buy new improved battle pass for next season.
When 1st battle pass came to games, I think it was Fortnite (damn I hate myself now for even typing it) and 2nd I know was Rocket league, both of which allow you to grind currency to buy next one. In case of CoD:MW in 2 seasons you can even free grind enough to buy 3rd, which allows you to buy next seasons without spending a penny.
Source: https://www.reddit.com/r/WorldofTanks/comments/fh0oda/battle_pass_wg_has_to_be_unique/
