I'm not sure if I find Pixelitis' editor's reasoning convincing, but in an editorial on the website they argue that the recent success of the isometric loot-driven Diablo III means that the Fallout franchise could be fairly successful while adhering to the original gameplay format:
I’ll start by saying that I’m not about to pull a No Mutants Allowed and go on a diatribe against Bethesda for its handling of the Fallout series. Although I still prefer Fallout 1 and 2, that’s not to say that Fallout 3 was a terrible game like many rabid Fallout fans claim – it was pretty decent.
In my eyes, Fallout 3′s writing wasn’t as great and the game’s overall atmosphere and soundtrack didn’t really gel with me as much as the first two games, but it carried the torch pretty well. I can say that New Vegas (which I admit I haven’t finished) improved upon it – specifically in the writing department, thanks to the addition of former Black Isle staff such as Chris Avellone, who contributed to the development of Fallout 2.
In an attempt to appeal to old-school fans of the series, Bethesda touted the ability to zoom the camera out far enough away to simulate an isometric experience and the V.A.T.S. system, which was described by some outlets as an evolution of the series’ turn-based combat. To the hardcore Fallout fan, however, these seemed like weak attempts at catering to fans of the original two games. Zooming the camera out all the way made the game impossible to play, and V.A.T.S. was merely a glorified cinematic version of Fallout 1 & 2′s aimed shot mechanic.
According to Bethesda’s Vice President Pete Hines, the decision to make Fallout 3 a first/third-person action RPG was an obvious choice.
"We’re not going to suddenly do a top-down isometric Baldur’s Gate-style game, because that’s not what we do well."
Regardless of their methods, I believe that now’s the time for Bethesda to make a ”risky” move in the form of an isometric Fallout game. Imagine a new Fallout with the graphical style of Diablo III – wouldn’t that be awesome? And when it comes to combat, there could be an option to make it real-time or turn-based, like Van Buren, to satiate both camps.
Few videogaming things would make me happier than seeing a true-to-form Fallout sequel, but I honestly don't see much of a correlation between the loot-driven genre spawned by Diablo and the post-apocalyptic turn-based titles from Interplay/Black Isle.