It's ironic that you're using that name, since I had made one with the same name recently. It wasn't very good, though, so I scrapped it.
What might have been...
If you perform a combo that uses more than 3 combo points, discard a card.
(I scrapped this because it doesn't affect a large number of matchups at all, and it wasn't all that interesting.)
Yours is better in that it's a lot simpler, but I'm not sure it does enough to be different from my take on Hard Times Mill. My Hard Times Mill punishes both players equally every turn, whereas your Morningstar Pass only punishes the player who wins combat each turn... But they punish the players they affect in the same way, by the same amount. To be clear, I like the idea! I just think that it's not quite unique enough yet.
Since the poll has a greater than two-thirds majority at this point, I'm going to close it and update the first post with cleaned-up versions of many of the Arena cards suggested here. I will not, however, post any there until their inventors reply to the PM I've sent them. Once the first post is updated, if an Arena card you have suggested prior to this post isn't there and I haven't PMed you about it, please let me know by PM if you want it added.
Edit: The first post is now updated!