As of now, it's a failure, but it's too soon to tell.
The packaging was a slop. In order to complete the set, you're telling me I have to buy a billion Zangoose, Ho-Oh, etc? So I'm paying $8 for 1 figure I need? No, I refuse. Do 1 of 2 things.
Make non windowed 1-3 figure boosters. You don't see what you get, you just get it.
Make windowed 1-3 figure boosters, that spread the entire set out into said packs. Like I have W amount of figures be available in 1 Figure packs, X amount in 2 packs, and Y amount in 3 packs, with Z amount in the Starters. In this case in point, W+X+Y+Z = Complete Set.
With a package plan like the latter. Kids can buy the Pokémon they like, when they want. Players can do the same. It's a plan that makes everybody happy.
Also, the lack of OP is killing it. We have a few leaguers that like to play, but without anything to play for, it gets stale.
Biggest flop? Groundbreakers starters in December. Boosters in...???. Organize the releases a bit better.