I respectfully disagree. I do think the soulbound rewards is pretty good. It doesn't affect the economy so they can just pump them out without any worries. Remember what happened with Chaos Legion set? Djinn Oshannus is now less than $1 and he's a legendary card. I don't think that ever happened outside Chaos Legion and there's a big coincidence, Chaos Legion, I think, is the only set that was added as a reward pack/cards.
I like the soulbound but the only complain I have is that they aren't strong enough to compete with the other cards. They're comparably weak and that's why they aren't used more often resulting to less excitement.