It isn't Star Wars, where the Imps are necessarily the big bad. Every one is a potential conquering bastard. Any hope for a ideal choice needs to be forgotten about. There's no Nord utopia, no knightly camelot, no benign empire, nothing. You just choose whatever works for you.
The Imperials are essentially the ruling class of Tamriel. Their forts are spread across the provinces, the natives of each land are more or less subject to the rule of Cyrodill and now they are losing their grip, which i am quite happy about. The way i see it for Imperial legion read: Roman empire (and i always cheer for the barbarians), and we are currently in the last days of this empire, they are losing their grip and are going down. Perhaps it is time for the native provinces to to be independent. But as i say, the Nord faction, which i would normally support, is not doing themselves any favours by being dikes to everyone who is not a nord. If i stick with the empire, they better pick themselves up, get their house in order and be kicking the Thalmors butt back to the Summerset Isle.