I'm seeing words like "useless low tiers" and such. I don't understand what this means, exactly.
As a competitive player with 13000 combined battles, I've always understood that Tiers 1-4 are essentially training tiers to get players accustomed to the basic mechanics of the game. Tier's 5 -7 are intermediate and designed to help people start to better understand the more comprehensive systems like AP overmatch and such. Tiers 8-10 are where competitive play begins and ultimately Tier 10 is where the majority of skilled play happens.
I literally just responded to a thread where a newer player was upset that a single unicum can walk into T5/T6 games and have a massive impact.
T7 is still my favorite tier because of the fact that you're often set up against ships that completely outclass you. T7 BB's are frequently overmatched by the AP shells of other BB's and cruisers have no heals. It's a madhouse.