I miss them because there isn't anywhere near enough costume discs for me this time around
The sheer number of power discs they could produce allowed them more flexibility in the random stuff they could put out there.
Now we won't say get costume discs for 1.0 or 2.0 characters anymore, because without it being random it's assuming the purchaser has the figure. But if it's released alongside the figure it makes more sense.
I wouldn't mind blind bags coming back if they got rid of "rare" discs. If everything had an equal chance, people wouldn't feel like they were wasting money. Like the lion king terrain discs that never appeared for me, had to buy them online.
Heck for me i would be happy if they did blind bags of just costume discs. Heck they could do blind bags of just Spider-Man costumes, he has so many!
Power discs could go so much further, even cross merchandise.
Like what if Disney infinity teamed up with hot wheels? You have probably seen those cars they release for marvel and Star Wars that look like characters. What if they came with a vehicle power disc so that car appears in game too.