I doubt it would actually be hard to implement. I've seen plenty Togruta male and female models with body types 1 and 2, heads, skin colors and face marks across the game, and the most important they have Ashara who is already implemented to wear most of the game's gear.
The only ones they had to implement now are the models for body type 3 and 4, from them I've seen none in game. But resources to make a playable specie from them, they got plenty to start from.
you have to remember those are static chars and a limited set of armor types. The one exception would be sith inquisitor companion, but again predetermined char, with set animations that DOES have clipping issues in many places.
Given 4 body types, 2 genders, and 3 armor types + all the adaptive armor, it can get rather difficult to update all art (or at least minimize the art) for clipping issues. Devs have said that togruta although popular does present a variety of problems. The Twi'lek was difficult enough and many art had to be tweaked for the lekku which only appear on the back and also tend to clip with items such as capes.
It may not "seem" difficult, but it isn't simply a point, click, and done deal.