The majority of those who seem in favour are long-time players and those who play a lot of T9/10. That's how it seems to me.
I've been using the last few events to grind up a few lines and it was actually enjoyable to play them (often stock) without being piñata to tanks 2 tiers higher. Yes, you get more XP if you do well against higher tiers but some tanks are barely competitive in their own tier, nevermind 2 higher.