I’ve been noticing a drop in rare+ items, too. Great to know I’m not the only one noticing.
Edit: Usually getting around 60% of all items as rare+ before the update; now I bought 100 boxes under this new update and so far I have received: 182 common, 103 rare, and 15 epic. That’s almost 40%, which is down from the previous %age. And this is while I’ve been at max lvl.