Slitherine

I just finished my first campaign, the Julius Caesar campaign.

If I were to play this campaign again, would I always end up fighting the same battles? Or do the battles actually vary, aside form how previous casualties effect my force/

the terrain for each battle is random, so each battle could be quite different even with the same troops (and you could vary your own troops, too). Probably you get the same type of battle in the sequence, as it is supposed to be somewhat historical. Also the type of battle might vary a little depending on the result from the previous battle.

The maps are redrawn and AI may purchase different units for its army.
That said, the decision tree for Julius Caesar is not dynamic.
The Rise of Rome Sandbox campaign is more varied.