Objection! There are more options than double jumps and air dashes. For example, X-23 has a lot of aerial mobility options without any kind of air dash, and so does Wesker. You sir, need to bring better evidence to court!
Nemesis could fire his rocket launcher downward while "firing" himself in the opposite direction a bit. Hulk could get an aerial Gamma Charge that goes downward (if you think this doesn't make sense, remember that he can already Gamma Charge while mid-air as a follow-up).
Basically, every character just needs a little something to make running under them something that has a thought-based component to it. Not every character needs a Foot Dive, just something.