I'm thinking of starting a new character to finish the CW on the Imperial side. I just don't know what race to choose. Then I thought that it would be a good idea to make a list with reasons (not very specific, personal reasons but more general, political reasons) for joining Imperials and Stormcloaks as different races, so if anyone needs inspiration, you can just have a look at the list.

I'm starting with the ones I've come to think of:

Altmer
Imperials: To fight Talos worship.
Stormcloaks: If Ulfric wins, the Empire will be weaker.

Dunmer
I can only think of them joining the Imperials; good reasons for joining the Stormcloaks will be appreciated.

Imperial
Imperials: Obvious reason is obvious.
Stormcloaks: The Empire has treated you or your family badly, and you see an opportunity for revenge.

Nord
Stormcloaks: Obvious is obvious.
Imperials: Same reasons as other Empire-supporting Nords.

Orc
Imperial: Orcs are also inhabitants of Skyrim. You dislike all that "Skyrim belongs to the Nords".

Redguard
Stormcloaks: You hope to get an ally against the Thalmor.

Please add yours! (Not including "the Imperials tried to execute me at Helgen"; that would be a reason for almost anyone to side with the Stormcloaks.)

Altmer: They don't want the war to end; no matter who is the victor.

Dunmer: The only reason I can think of is to maybe throw off the prejudice of the Nords?

Orc: For awhile my characters did not support the Empire, due to their mistreatment of their people, the Orsimer, over the years.
However, my main, whom is a bit of a revolutionary, sees the Empire as a means of stability for the orcs.
Thus he is an avid supporter, in hopes that, like Gortwog, he can make the Orsimer a force to be reckoned with in the world.

To get back on topic, yes, I could see an orc Stormcloak. The Empire didn't handle Orsinium well, and did not reprimand the Bretons or Redguards.....

Redguard: I could see one supporting the Empire, in hopes they'd bring stability back to the world.