I swear, if I had the ability, I'd do a questmod about choosing a 3rd option in the Civil War questline: brokering a peace between the Empire and the Stormcloaks, then both groups kicking the ass out of the Thalmor (beginning with destroying their embassy, then silencing them and their spies so Skyrim would become a silent territory for them). Having in mind their mutual hate for them, you could think "the enemy of my enemy is my friend" could be relatively easy applied there.
Besides, Tullius was sent to Skyrim to "solve the situation there", without being given any specifics (AFAIK). And brokering a peace is a solution as good as any other, so technically he wouldn't be contradicting orders.
By now my next character (well, a remake of my favourite one) will be more like 75% Stormcloak, but still neutral in the fight. Fortunately, being an outcast from Soltsheim and somewhat individualistic (althought proud of being a Nord), it kinda fits him.