Im Done

[Zojha]

What changed?

They tightened the matchmaking?

It's a constant back and forth between tighter matchmaking and better queues. The most recent change is from 4.1 patch notes:
"Matching algorithms have been adjusted for the Feast (4 on 4 - Ranked Match) to ensure players are matched with others of the same or an adjacent tier."

Before that, you had a two-tier spread. I can't remember what was before that, only that it keeps going back and forth.