People need to understand that MMORPGs and single player RPGs are two very different beasts. Yes, Darkfall Online had first person twitch-based for ranged combat and Mortal Online had first person real-time combat. However, we have to keep in mind these were niche indie MMOs created to try and appeal to a different audience from the mainstream MMO audience. That being said, AAA MMOs all basically follow the same principles: third person combat, auto-target, tool bar, class system, level cap, etc.
Real time combat is not a niche or an indie idea, it's just that the developers who made those MMO games were indie, hence the products were never going to be a huge success. If a AAA developer actually did a polished job of it in an MMO, it would benefit everyone. Skyrim was the best selling game on Steam of all time at launch, and one of the biggest games ever. COD and Battlefield sell dozens of millions to all sorts of casual and hardcoe gamers, relying on an infinitely faster "twitch" system of combat with up to 64 players in a single game. And it's not as if MMO gamers and non-MMO gamers are a different species - in fact, the distinction in completely non-existant. Everyone I've ever known to play MMOs also played regular games, and virtually all of them love Elder Scrolls. For certain, they don't boot up a game with a reticule aimer and go "damn, this click-to-attack is so difficult." If there are more than a hundred people who think like that on the entire planet, I'll eat my shoe.
MMOs and single player games started as "different beasts" because of technology, but increasingly that's become irrelevant. And yet this weird mentality persists that an entire genre of game has to play exactly the same based nothing but the fact of it being online - and it's led to this misconception that if you implement any different features, MMO gamers' heads would explode when faced with the 20 minute learning curve of point-mouse-and-click - or at least, for those few dozen people on Earth who play games but have never played a shooter or any other real-time game before.
And again, if Elder Scrolls is such a big title, why would we honestly fear implementing the exact same gameplay that millions of people already recognize from that title? It's like saying, "Hey, let's make a TES game, but the market might not like the medieval fantasy setting (even though people play games like this all the time), so let's make it a 21st-century corporate drama in which you play a lawyer voiced by and modeled on the actor Steve Buscemi."