Well, I painted up all of the new Descent for my son’s birthday about three months ago, and we played once. I think it was just that I came at a bad time, and we’ll get back to it, but it certainly is a bit of a letdown. But my kids adore Mansions of Madness, which was what made Descent seem so promising (and Imperial Assault, once I get that painted up).
Mice and Mystics has great elements, and I’m glad we have it simply because my son played with those minis for many, many hours, but it’s too long and slow for (my) kids, and too tactically flat for my liking.
If it would be dungeon crawly enough for you, Too Many Bones was an astonishing hit with my kids when they were about 10. The difficulty levels are wide enough that you don’t have to hold the kids’ hands too much—just choose a low level and they can make their own choices and cope with the consequences without absolutely dooming the party. It’s the first game that really drew my kids out of their excessively cautious gaming shells. Previously, they hated to lose (or even take damage), but TMB is just so silly and the characters so flavorfully reckless that the kids were sort of swept up in semi-roleplay. It has all sorts of genius decisions, excessively nice parts, wonky imbalances, rules overcomplications so ornate that I’m not sure whether there are actually big gaps or I just missed stuff—it’s a bit of a messy experience. But it’s also a co-op, so you can just do what seems reasonable and not fuss yourself about it too much, and it sings.
Jaws of the Lion does seem like a superb way to get into Gloomhaven, and we had some fun with it, but interest petered out after 7 or so games.