Is that definitely a shrine to Talos? Could it be an another ancient Dragonborn? Sorry if it has been confirmed, I must have missed that info.
There's a piece of concept art showing the same shrine, and it's labeled as "Shrine of Talos" or something to that effect, so I don't see any doubt that it's a shrine of Talos, on the other hand, there's absolutely no indication that the snake on it is supposed to be a Tsaesci, since we've never seen them before and don't know what they look like. What little lore we have on them identifies them as snake people, but that does not automatically mean that anything that looks like a snake is automatically a Tsaesci, and in fact I highly doubt that snake is a Tsaesci, or if it's meant to represent them, it's not a literal indication of what they look like, because it is in no way humanoid and does not even have any arms, which is pretty impractical for an intelligent race commonly attributed to have provided the origins of things like katanas, which would be hard to use without arms, I think, unless all Tsaesci are telekinetic.
In any case, I'm guessing that if Akaviri races were to play any important part in Skyrim, we'd have heard of it by now, that doesn't mean we can't have a few quests or locations where Akavir-related things play some degree of role, I mean, I don't recall hearing that we'd see a quest where we had to go to a fort once occupied by Akaviri invaders to retrieve an Akaviri amulet in Oblivion, but we got it anyway. However, I think having Akaviri races playing any sort of important role in the game would be something Bethesda would feel is worth mentioning.
Oblivion was accurate in lore just fine, it only had a discrepancy, all of which are explained by the fact that they have only a few accounts about Akavir and they were written by people that were speculating about them, which is what makes TES's lore so great is because it's much like real life how people can spread misinformation.
Don't expect fans to be capable of grasping that. If they see anything that isn't EXACTLY like how they imagined it to be, it's automatically "not accurate", which makes absolutely no sense when you consider that the "not accurate" lore comes from the people who create the lore, and therefore define what is and is not lore correct, and thus it cannot be inaccurate unless the creators actually recognize it as non-canon, which they clearly don't (Yes, I know that the elitist fans here hate to admit it, but it's the creators of a setting who decide what is and isn't correct in the lore, not the fans, but I know that's extremely difficult for some people to grasp.) never mind that the original account which what we're shown is percieved to contradict is both old, vague, and from the source of an in-game book which may not be completely accurate to begin with.
I tend to just accept the theory that the Tsaesci had not actually killed all Akaviri humans and used them in the invasion myself in regards to the skeletons at Pale Pass, because the alternative would be that the Tsaesci are not actually snakes at all but just humans in whose culture snakes play an important part, which is a much less interesting option, so in absence of evidence to the countrary, I'm inclined to just believe the more interesting theory.
Very similar to the Khajiit. Or at least that's what people believe. It might become a bit confusing to have two cat races in it.
I don't see how it would be less confusing than having multiple elven races or human races in the game. And just because both races are based on felines doesn't mean they can't be different enough to be easily distinguishable from each other.