@Lyaksandra I would disagree. Ahsoka's species (Torguta) may look impressive in static shots with long tendrils and tall horns, but for such an animated character as her, they would be impracticable.
The actress would have a very hard time pulling off the same choreography if she was forced to wear tendrils and horns of the proper proportions. They would be cumbersome and get in the way unless the production chose to make them CGI. Which would have the issue of feeling detached from the actress and still cumbersome looking. Also, from a fighting stand point. Long tendrils and horns would be vulnerable spots she would have to expend energy defending and would leave her open for attack. They only complicate scenes and lessen what she can do.
No, this is an instance where a soft retcon should be welcomed. Short horns and tendrils give the character a much more pleasing silhouette and becomes more reminiscent of hair on a regular human being. More so than the "canonical" depiction that just looks like a big octopus monster latched onto an actor's head.
Even the leather head band does wonders in transforming an otherwise jarring separation line between the actress and the costume into something more reminiscent of a hair band. Reinforcing the idea that her tendrils aren't a foreign body, but her specie's hair. Also from a practical standpoint, this allows for a more substantial harness to be incorporated into the headpiece in order secure it to the actress' head. Without it and with the larger proportions it would sit on top of her head instead of around it and be more prone to shifting on screen.
@GionSpot Really good work! This is how the Clone Wars should have been animated!