Look, I'm new to the game but I see there is a lot of discussion going around about this on Reddit and here. I share the sentiment that the game can become extremely frustrating when you can't actually play because they pair you with impossible competition.
Personally, I think its good to pair with hardcore competition, but in a manner that makes sense. If you win in Arena for example and each time you win they pair you with a +10% difficulty or Hero Rating average, and slowly builds to it - Great, that makes sense.
But literally on Win Streak 7, I got paired with this.

What the hell? It just doesn't make sense and it's very frustrating when you are trying to build up the x3 bonus..
And I'm not even going to go into Battlegrounds....
I just wish KABAM worked on this.