I love top-down isometric games, and as you can see by the avatar I'm experienced in Toaster Repair, but New Vegas is proof that it's not the engine or first-person perspective that is holding Bethesda back - it is Bethesda's terrible, awful, garbage writers.
You're missunderstanding my intentions. The point is, for me New Vegas could offer the best writing and role playing that any Fallout game has ever seen to this day. If it also doesn't offer a top down and turn based gameplay, then it simply lacks the necessary 'Fallout' experience to call it self the best Fallout game there could be.
See, when I played a game like Jagged Alliance for example, then I get a lot of enjoyment from the fact that it is up to this day, one of the best turn based games. The turn based gameplay is a crucial experience for me. And it also defines the game. Any Jagged Alliance sequel, that even HOPES to come close to this quality and experience MUST(!) include turn based gameplay. Or it will never be a whole Jagged Alliance experience. And a game like JA or Fallout, as we have seen, can be easily turned in to shooters. But, when I look for the Fallout experience, then I am not looking for a shooter first.
The Fallout 1 and 2 developers chose turn based exactly for that reason as well, to provide the players with a certain experience. This is how I played Fallout for the first time, and this how I will always see the ideal Fallout. As a turn based game with a top down perspective and a tight role playing experience. You can eventually make a game, like New Vegas, and remove the turn based combat in favour of a more shooter-like gameplay, but then it will lack the Fallout gameplay of the original games. And like I said, as we have seen with Wasteland 2, X-Com, Age of Decadence and many more games which have been released recently, that turn based is still as viable as ever.
For me, a game that want's to pride it self as the high-point of the franchise, can never be that without turn based and top down gameplay, even if it had the best role playing experience ever. Just as how a Doom game, has always to be a first person shooter and not a top down strategy game, even if it was the best strategy game ever.
So while I do love the top-down perspective, I also found the first-person perspective of New Vegas to be a wonderful way to present a Fallout game when done by competent writers.
That's your personal preference however. I like to think, that the best Fallout experience can be only found by following the original concept and idea that the Fallout 1 developers had in mind when they chose their gameplay and narative. They chose the gameplay first, and the setting later by the way. And this was not by considence. A lot of first person games and real time action-games have been released at that time. And the Fallout 1 developers, chose to go against this because they wanted to provide a unique experience. One of the ideas was to emulate the PnP gameplay to the PC. And you simply can not do that with first person and real time combat. But this is the core of Fallout. What ever if that is now something that some Fallout fans prefer or not.
Fallout New Vegas is a great game with a lot of fun and a great role playing game too. But, it sadly does dillute the Fallout experience, when you take Fallout 1 as blue print. And I could never see New Vegas as anything but a (very well made) Spin-off.
