I will agree that it was nice to see Cana get a bit more use of her abilities without the craziness of the S-Rank exam or the Tournament. Only thing I don't get is why she didn't just seal the explosive in a card but maybe it just doesn't work that way (and it'd leave the guild intact, can't go an arc with that happening).

It's a neat little trick that let Mira Jane get loose even if it is absurdly convenient and I'm a little disappointed that Lisanna and Natsu nabbed the demon like that, it seemed they'd be a little smarter than that and realize "hmm... big hole in the wall and no prisoner, maybe I ought to report this" but I guess the overlord list can't ever make it into an actual story.