Weird. I mean, I didn't think there even was a t7. I thought that there were only 6 tiers. Let me go back and check.
Okay, there are only 6 tiers. I tried the hardest tier and went in with Rey + RHBros, Holdo, and OG Finn. Lost RH Finn to a counter on RHF's first move. Brutal, but I won then level on that first try without reading any guides or even the event info or doing an re/modding.
I'm not saying it's easy. I got a little lucky with a well-timed SLKR swipe reducing Holdo to yellow health which allowed me one more whirlwind than I thought I was going to get. Even so I beat it first try so it can't be THAT hard.
I'd say that there's something going on there, but it's not a recent increase in difficulty.