No, not agreed. Those descriptors are generic as it gets and can mean a variety of things. Also the 3D models basically look and move like 2D sprites, they are not an inch more realistic than before. Pretty sure we'll understand the rating after playing the game (unless it was just arbitrary).
Hmm, possibly. True, we'll have to wait for either the ESRB to upload a description of the game or for people to play the game (or somehow get Capcom to tell us, which I doubt they will). Though it should be mentioned that AA Investigations got a T for MILD language, violence, and suggestive themes. The ESRB does have different levels for descriptors (mild language to language to strong language, blood & blood and gore, suggestive themes compared to sexual themes, partial nudity to nudity, etc.). Granted, still kind of generic as you said, but just throwing that out there the ESRB does try to be specific as to the level of content a game has.
But yeah, think we're just gonna have to wait & see why it got a M by playing the game ourselves. I'm just not expecting it to be a huge jump in ESRB-related content.