You’ll get more speed if you add propellers

There is sort of an in-universe explanation for this, most weapons powerful enough to actually damage stormtrooper armor were outlawed shortly after the Empire was formed.

Note: This is not an actual scene from the movie. Sha’a Gi was killed by General Grievous during the clone wars before this movie would have taken place.

Really? Hmm, normally it would have tracked you down by now

Stare closely into the yellow circle, soon you’ll know