I am really impressed with the amount of work you have put in this post!!!
I really want to play a naga since warcraft 3!
I really like the fact that you are pushing for the actuaal naga with actaul tails and not some 2 feets or 2 forms concept that imo would make the race lose their identity.
To anyone sceptical about the tail, and animation, especially with mounts, i can tell you that it is not a major problem and i will put here the reasons :
The issue prople have is to imagine how the way characters stand on mount work, actually, it is not like if your character was actually sitting on it, actually no, you summon a mont which ātranseformā you into āyour char on this mountā, its not 2 entities put over another, but one block, one being, that your character turned into, you can see it by the fact, even the playable race at the moment lack some animation and feel like āgluedā to their mount.
Now if you paye attention, when you use your mount on a vulpera, or a draenei or a dracthyr, you can see that their tails gets into a very specific position which happen only when they are mounted (again its because they āturn into thisā)
Knowing this, there is no issue with the naga regarding mounts, blizz just need to come up with a posture that can make them be on the mount, they actually need 3 and for these 3 there is simple ways of doing it :
1 - Horse spread legs mount pose : On this nagas can use the amazon way of seating, or they can roll their tail around the mount.
2 - The āchairā mount pose : Easy one, you just need to imagine yourself, putting your legs together, on your chair and thats it, just like naga have one leg, you have one too if you put them together!
3 - Seating on ground : Another idea could be to make them be coiled like a cobra, this pose can work perfectly for their drinking/eating or even simply seating animaiton!
Now, their a big avantage with the naga, and that is, both male and female will use the same animation set for their lower body, (if blizzard want that is they can make different for both) which means, if blizz want they can just work only on one model and then the other will be done!
Now the āproblemā is, that this model will be hard to recycle, as we know, blizzard love to reycle their model, and unless they make up a lot of snake people, the work they will do on the playable naga will be hard to re use outside of the nagas.
I want to add one more point :
Myself i would love if our naga leader would be Azshara, to me she could be an ally in the future, a bit like Illidan, and i would say her relationship to the playable naga would be the same as the one Illidan have with the playable DH, which means, that she would not be around much, but still the playable nagas would aknowlodge her as their suprem leader.
The one that would then lead the naga in the spotlight would be Narājira, the battle maiden from Vashjāir!