I actually think that Burns was remarkably well balanced considering the absolutely insane scope of doubling the number of Masters in the game. Sure, there were a couple of OP ones and a couple of lackluster ones but I think that no one could've gotten that amount of stuff right on the first try.
Madness is a sadder case, IMO, since the scope was so much smaller and the OP stuff being so far above the curve.
But all of that said, I very much doubt that they are intentionally making the new stuff OP. There is always the incentive of making new stuff appealing and erring on the side of too powerful instead of too weak kinda makes sense (making stuff that doesn't have any impact seems like a bad idea even from the players' POV) but I very much doubt that anyone in the design team is going "let's make Witness completely bonkers in order to make it sell well."