Some time back I tracked the drops from running Ramboy 1000 times on normal difficulty. Box contents were roughly:
60.5% Common Items
34.5% Rare Items
4.8% Epic Items
0.2% Legendary Items
Since the recent addition of content and the nerfing of drops, box contents have been roughly:
75% Common Items
22.5% Rare Items
2.5% Epic Items
0% Legendary Items
That means you get:
24% more common items than you used to get
35% fewer rare items than you used to get
48% fewer epic items than you used to get
Technically 100% less legendary, though I would guess it is likely more like a 55-60% reduction if the nerfing follows a sequence.
For the data gathered since the nerf, I made 100 runs. It is a smaller data set, but I think its large enough to support my numbers.
I also tried buying 50 silver boxes. The results were close enough to assume that silver boxes now have the same drop rates as mix boxes. So they’re both pretty bad.
Basically, you’re getting a payout of at least 30-40% less. That also means it will take 30-40% longer to level up your items.