Imperials have the resources, but their ships are typically stock advanced rather than modified. If anything they should have less upgrade slots, and just be able to field more ships.
Well, I don't think that's representative of the whole picture, but what you describe is completely possible in the game already. Generic pilots, don't take upgrades, spend the extra points on more ships with generic pilots and no upgrades.
Unfortunately, if that's the Empire's "thing" in your mind, the game currently allows Rebels and Scum to do the exact same thing. Currently, the Empire doesn't have a "thing" that's unique to them.
Also, you're assuming that the Empire's upgrade slot would be a new type of ship modification. I was thinking something more logistical. Upgrades that represent the Empire's limitless supply lines. Things that have been mentioned in the thread already. Like reinforcements, off-table capital ship support(fancy space word for artillery strikes), mid-battle rearm and repair services, etc.