>>280419489
>This results in the overall themes of the series becoming a lot more clear and pronounced in the movie
That's really the gist of it. The movie doesn't add that many new themes (it does, though, just not all of them. It has more focus on communication, family/companionship, responsibility... it basically adds a bit of that Christmas movie outline to the existing setting). But for these existing themes they're repackaged and put in another setting with similar but still different stakes and implications.

>whilst cutting almost entirely on the comedic elements present in the original series
I would say the only thing I regret about the movie isn't that it removed some comedy/made the overall tone more serious and solemn but rather that it lacks the "episodic creativity" explosive energy of the anime. It's a more conventional type of story, which comes with pros and cons