I agree that some new species would be awesome, I love the Cathar, so I was very glad when they showed up. However the species you've mentioned here have a common problem, that might MIGHT be a problem. Helmets. While all of these species have a humaniod body, which is vital for gameplay, none of them can wear helmets. Kel dors head shape is too different, Nautolan's (I'm assuming that's what you meant) got too many head tails, the twi'leks are able to wear helmets despite their lekku because they have only 2, not that much, I can't remember the specific number of head tails a nautolan has, but it's a lot more. They're heads are also a bit of a different shape to accomodate that and the Togruta have their head spikes. The sith inquisitor companion Ashara is an example of this, since any helmets you equip her with don't show up.
Honestly I reckon the Kel-dor might work, and I'd love to be able to play as one of them as well, but aye, doubt the other two are gonna happen :/