I completely disagree about the 3D environments not being the reason people loved the series. I for one was a big fan of them and they made you feel like you were looking around for clues MUCH more than any other adventure game series.
If there was a new Tex game that didn't have you looking around environments in 3D I would be heartbroken. It wouldn't really require a big budget to make them look quite good.
I agree that the 3D environments add a lot to the games for me as well, but I think it would take a big budget. (on a non-fan fiction level)
i really think to make a new, 3D tex murphy game work well with modern systems, and with modern expectations of games, they would probably have to license a game engine and build it right. anything less would be asking for a huge bug-sandwich.
just my 2cents.
Oh, I also wanted to say that I think this was a great interview and I really think this kind of content adds a lot of value to the GOG community. :)