Nord, Redguard, Argonian, and maybe Orsmer could go stormcloak, anyone else just doesn't make sense unless they've got some extreme empire hatred going on.
In the best interest of skyrim as a whole, the stormcloak rule is just an obviously bad idea; corrupt, war-loving leadership with questionable claim for the throne and loads of racism. The only reason empire wouldn't be the obvious choice for most players is because they were played as being incredibly torture/execution happy.
I personally am pro-thalmor and would side with the empire if suddenly thrown into the TES mythos.
