Hugin & Munin has lackluster base stats, and on average, I would not expect the Response ability to be worth it. Your hero is usually the only character you can ready for value and not just tempo (though Aerial decks have some notable exceptions, and one basic attack from your hero has a low chance to kill a full-health minion. That being said, Hugin & Munin's traits are what make it interesting. "Aerial" has lots of synergies like Air Supremacy, "Asgard" gives Thor and Valkyrie another target for The Bifrost, and "Bird" makes this searchable by Sam Wilson's alter-ego ability. Having 3 total traits makes H&M very appealing for a Strength in Diversity deck, especially because Asgard and Bird are redundant with very few other allies. Lastly, Thor, Valkyrie, Winter Soldier, and any future heroes highly incentivized to engage minions will find this card useful.