I am hovering at the moment. I read a lot of pro-Stormcloak arguments that made me doubt my choices. But if you'd have to sum up what's so good about the rebels and what sucks about the Empire, what would you say?
The DrunkenMage strikes.
The Empire is the best hope against the Thalmor: Are they? Majority of the Nobles are expressing an desire of peace between the Empire and Aldmeri Dominion. The Empire hasn't shown any willingness to act against the Thalmor, they're just sitting around on the defensive, with the Emperor, Titus Mede II assassinated. It then casts a great shadow of doubt over the Empire, because the Elder Council has been known to not work for the interests of the Empire, but their own pockets. Through dialogue we also know that Maven Black-Briar is bribing the Elder Council.
The Empire can't send Tullius any Legionnaires, because they're all on the Aldmeri Dominion's borders: Except that isn't the case, we also know from a letter sent to Maven Black-Briar from the Imperial City, that the Council is giving her Legionnaires to meet her Mead at the border, and personally escort bottles of mead... Talk about backwards priorities.
The Thalmor are only given free reigns in the Empire, because of Ulfric Stormcloak: Dialogue from Delphine, and even the Thalmor contradict this unsupported statement. The White-Gold Concordat, give the Thalmor free reign.
The Stormcloaks are racist: They're nationalistic, not racist. The Stormcloaks give no racism, in fact Galmar welcomes other races. They're allowed to join the Stormcloaks, just like any Nord.
Ulfric Stormcloak forces the Dunmer to live in the Gray Quarter by law: Except they weren't forced, the Gray Quarter was around long before Ulfric Stormcloak, the Dunmer arrived in Windhelm as refugees and the Nords gave them an entire district for free. They also don't want to leave the Gray Quarter, and two Dunmer actually live outside of the Gray Quarter.
Ulfric banished the Argonians: That he did, but there is possibly racial tensions between the Dunmer and Argonians. That seems to be suggesting even violence, the Imperial sided Jarl won't even let them inside for their 'safety'. Interestingly, Imperial supporters won't mention that an Dunmer in Windhelm forced an Argonian to go without food for two days.
Stormcloak Militia has no hope against the Aldmeri Dominion: Yes, a Militia doesn't have any hope. Except the Stormcloak army is being trained by ex Legionnaires at the end of the war, so they'll even be able to match, or possibly be better than the infamous Legions.
Skyrim needs the Empire for trade: Yes, and so does the Empire need Skyrim for trade. The East Empire Company, stays out of politics and there is no reason to believe they would simply stop. If the EETC is willing to look into trade deals with the Thalmor, would they be biased against an independent Skyrim?