I mean the weight of their confrontation. The way I look at these things, if you ignore the fact that it's Bats and Supes, what part of the trailer is actually looking like exciting cinema on its own? To me, not much. It's an issue I have with a lot of teasers these days, where I feel they're not trying to sell me on the movie but simply expect me to care just because of the namesake.
For an example of how it's done right, look at the Furious 7 Superbowl Spot (basically its teaser). It's a minute long, explains the story simple and clearly, boasts some of the action and basically tells you exactly what you can expect and why you should want to watch it.
To get back to the BvS teaser not carrying much weight to me, I've seen nothing in it to suggest that this is going to be an amazing one of a kind experience. And I think even though it's just the first teaser (of surely many more trailers to come), that's not good enough for the first time we're going to see Batman and Superman on the screen together.