Well that's certainly not an arbitrary, self-serving distinction.
Clearly, the Cap trailer was better IMO. But I'm not against X-Men being more of a soap opera than a traditional beat-em-up action film by traditional, heroic characters. I do agree with Uncanny guy in that sense, because it fits the nature of the comics and franchise. Mutants are freaks. They're hated by normals, they can't get along with each other, the spectre of death always seemed to hang heavier over them than over other characters and teams. Ultimately, their existence seemed to be more of a genuine, constant struggle than guys like the Avengers, who in my mind were more in line with the classic JSA--they were mostly loved by the public (statues erected in their honor, etc.), could take extended sabbaticals for various reasons (the mass exodus of members before issue 20), and be comfortable bachelors, scientists, and leaders of industry in their spare time if they chose to. The X-Men couldn't do those things for the most part. And their victories were never fully satisfying ones, because they were always battling for the survival of their own kind against threats from bigots. This is prime, soap opera material. As are Spider-Man, and Batman in their own ways, as those respective stories lend themselves to an examination of internal conflicts and motives more than just good guys responding to external threats to the world broadly defined--which is more Avengers, Fantastic Four, and JLA material.