The drifters are very underused for starters, but late game become completely forgot, and the commander is of limited value at certain stages of the game too.
So if drifters could be used to create EMP blasts, they could temporarily cut power to all marine units, structures, abilities and lights in a small radius.
Great for: - disabling ARC movement and shooting for short duration (max 5 seconds) - disabling jetpacks for very short period ( 1-3 seconds) - disabling lights for short duration (max 5 seconds) and this would only be a small area, not the entire room - disabling turrets, phase gates etc (max 5 seconds) - disabling research progress on marine buildings. (max 30seconds, can be welded to restart early). - cancellation of nanoshield. - disabling movement on the exo suit - maybe just slow down?
how this is done is up for discussion of course, it could be either an ability on the drifter with a 30 second cool down, or a passive ability in a small radius, or a large radius ability that sacrifices the drifter.
because the drifter is fairly weak, and because it uncloaks during movement, i think its already balanced as marines could shoot it down, but thats already a benefit as they would change their targeting priority. A clever khammader could place drifters in good spots as scouts as you already do, but then would be able to trigger emp as a trap etc.