I would have thought so. The Legion will probably be better trained and equipped but a lot fewer in number. The only people I can envisage supporting the empire are nobles, rich merchants and others who have a financial interest in Skyrim remaining part of it. It all boils down to money, just like real life.
EDIT: Big thanks to Fortis Ignavus for the info! :thumbsup:
Err what? Why would everyone else just arbitrarily support leaving the Empire? You can spin that around the other way too. To consolidate their power and ensure the iron grip of their local influence, I'd imagine the Stormcloaks are full of nobles, rich merchants, and others who have a financial and political interest in consolidating their power.
I have a feeling both sides will be painted as sympathetic, but I highly doubt it's purely based upon economic lines.