I just wish they were more clear on what they meant by this.
Is this restricted to just our own party or is it going to matchmake an entire lobby within 1 tier of each other?
And by one tier do they mean plat-diamond or plat4-3?
I have many questions
If it matchmakes the entire lobby within one tier of everyone then I will be happy that predators will no longer be in my diamond lobbies
This is referring to partying up with your friends to play a Ranked match. Currently you can party up with your friends and play Ranked no matter what your rank/their rank is. For Series 3, for Platinum and above, you can only party with players up to 1 Tier away from you.
To be explicit: Tiers are Bronze, Silver, Gold, Platinum, Diamond, Master, Apex Predator. This partying restriction means if you are Platinum, you can only party with Gold -> Diamond. If you are Diamond, only Platinum-> Master/Apex Predator. (Master and Apex Predator are treated as the same tier for this partying check).