Welcome to my world fan, they made this change at the start of chapter 5 without any explanation whatsoever. Every patch, every maintaince I check to see if the 80% requirement has been removed, I've posted threads in this section a few times over the last year and also post after my results on patch day in the undocumented changes thread. With that said, I can only think they honestly don't care about that aspect of the game, which is sad because as many will point out it more than just being able to fight and try skills, it was a gathering spot not to flex anything but to hang, chat and get that break from the monotonous.
The Euro side of this game has a very, very active "twink" community as in their arena brackets have always been heavily populated, so multiple instances of a 3v3, even 6v6s at 1-29, 30-39 etc. So they are sorta effected but not seeing as they have such a higher population across the board and of course more servers and such. I think most of the threads regarding the change are locked, I believe a few on the EU forums were at least over the last year.
I've all but given up on it, sadly a place in a game that I really loved was just taken away from myself and countless other players in the game. What I really don't understand and what they failed to understand is that it's a point of revenue, amongst other areas in the game, they just overlooked the fact people simply spend money to twink toons, just as simple as that and they don't care, they don't want my money because they made the change, that is how I see it.
I've thought about making petitions along with some of my threads about this but it just falls on blind eyes, I even went as far as to explain, thoroughly to Dio about the intricacies of how they are losing from the change but alas no luck with the exception of some sympathy, which isn't what I'm looking for. Now that they incorprorated it into quests again (can still get daily tokens from doing it once a day), they might actually consider the change.
Side note: Sadly in 2 patch notes there was mention of arena changes, one was about karros and I Think the other just mentioned a change to it but even so, they did not change anything to karros or the arena overall, this was 6 months or more ago.