Everything was good in that I didn't mind the "robot+monster fights-to-everything else" ratio being skewed toward the latter (appreciated that the two actually leads didn't kiss at the end for once), but it honestly could've used a few more unadulterated fight scenes.
I feel like it suffered from the desire of some action filmmakers to make their stories have the entire world be at stake with a lot of justification/build-up for the action scenes rather than make their action scenes be compelling enough to carry the whole film. I think of how Dredd was "a (bad) day in the life of Judge Dredd," rather than "Dredd saves the world," and it still managed to capture the essence of the title character, was compelling with good pacing in regards to action.
A lot of secondary/tertiary character screen-time could've been used to showcase some of the jaegers and establish them as characters so their "deaths" are upsetting for reasons beyond "they were, like, just introduced."
The film being so damn expensive probably allowed only the fight scenes we got, of course (which were fuggin good), but ideally, your robots vs. monsters movie shouldn't have long stretches completely lacking robots vs. monsters. The storyline, characters, backstory, Etc. were all good, don't get me wrong. However, people are watching this to see those fights, not to see the humans save the world. It'd be like if Jackie Chan's Drunken Master II had one fight scene at the beginning that kind of cuts short, a glimpse of the end of a fight a little while later, and then a bunch of fights together at three-quarters through the movie.
Don't know how well-over a Pacific Rim taking place during the heyday of jaeger piloting in place of what we got would have gone, but it may have made for a more rewatchable movie. The sequel could've been the "save the world," movie and given various parts of the movie room to breathe (final monster not being an actual fight, the whole "good ol' days" portion). But, again, don't know how that could've been satisfactorily done.