Changing tactics isn't the easiest to process. I don't have Nidhoggr. Don't remember facing one either. Why not just drop mana cost. That's easier to process than tactics.
What is same card was 50% cheaper to use? That's easy to wrap my head around. So what if there was a poll to check that?
PS: I'll make one!
I voted on the poll. Those were some interesting results.