Agreed, rates on these are the worst.
I've gotten 2 rares, one from fusion, one from a pull, a moderate pull on uncommon, and a whole boatload of commons.
The fusion irritates me greatly. Nearly every other game, to the point I can't pull one from the top of my head, that has both fusion and tier mechanics has the fused card automatically advance a tier. I would rather toss some more cards into the pot if it got me the next tier, instead of a well known crapshoot
The fact that this does not do that feels like a bit of a slap in the face from the developer. We know they try to get every bit of money out of it they can, and the game is still very playable...and winable...without putting money in, but sometimes they take it a bit too far