
I feel like you're oversimplifying the HA plot to "he fights bad guys." HA is a more effective film than DH because intertwines the coming of age aspect into the action and comedy. Yes it is more Christmasy, but that's relevant beyond the plot. It goes hand in hand with the coming of age aspect, and is more effective at creating nostalgia. In DH, the plot drives the protagonist, but in HA the protagonist drives the plot, and that makes Kevin a much more interesting character.
I could argue the same for you simplifying DH- the inciting incident of Kevin being left behind makes his family (mostly his mom) immediately make their way back to him. But McClane is already estranged from his wife and kids and has to make the journey himself reunite. I would agree that the plot makes Hans more of the protagonist at a point and John is wrench in his plan, but I think that symbolically speaks to fighting for Christmas as a whole.
I guess they both have a theme along the lines of family, courage, and the so-called "indomitable Christmas spirit". But while DH reaches this conclusion using cool guys and explosions, Kevin has to overcome much worse, such as doing things like...going to the store alone...meeting your neighbors... and walking past the basement furnace...scary stuff. This is the strength of HA. While DH takes a grandiose path to teach the lesson, HA's approach is MORE effective bc it's more real to the audience