Stormtroopers are exactly that: fearless, ultra-loyal infantry trained and equipped for close assault. Their officers (seen on on the Tantive) wear black uniforms, different from other imp officers who wear olive green or brown. I understand them to be a distinct corps, not vastly unlike the way the Waffen SS was separate from the German 'heer' in WW2, and used very often to spearhead German offensives.
Stormies are not the only imp. footsoldiers to feature in the films. In all three OT films we see black-clad soldiers called Death Star / Imperial Navy Troopers. These guys are employed, on the DS I, on Star Destroyers and in the DS II's shield generator bunker, in a defensive/security role. As assault troops, stormtroopers don't guard prisoners in cells or stand sentinel in the corner of a SD bridge. These guys do that.
In RotJ we also see guys in grey jumpsuits and open-faced helmets not unlike WW1/WW2 German stahlhelms (also worn by Veers) driving AT-STs, and guys in similar grey jumpsuits but with white Tie-fighter-pilot-style helmets driving AT-ATs. I do not understand any of these chaps to be 'stormtroopers'. I can therefore see a role for cheap imperial army infantry in the same grey jumpsuits,used predominantly in a defensive, static role. If that was the only EU concept to survive the Disney purge, then that would suit me.
Sign me up for some imperial army troopers, and also some imperial navy troopers.
Ta very much.