It will never be more than a gimmick, and I completely agree with Friedkin's comments.
If you think of your favorite movies, and classic movies from years back then you will find that it is primarily the story, the acting or the direction of the movie that keeps bringing you back to it.
Rarely do we go back to watching movies because, for example, the effects were great. And the prime reason for that is that effects will always date.
Does anyone still think the effects in the Matrix trilogy are revolutionary, and worth watching over and over again? Or the Jurassic Park movies?
The problem with 3D is that by definition it distracts the viewer, and dictates that we should be concious of the depth perspective, rather than the aforementioned base elements that are essential to the enjoyment of a movie.
And we have been here many times before with 3D...from the early 50's movies such as Bwana Devil, Creature from The Black Lagoon, It Came From Outer Space (the latter two have interestingly attained classic status in their 2D versions, most people would never have even seem them in 3D)... the 60's with The Bubble, Frankenstein's Bloody Terror... the 70's with it's plethora of 3D porn... the 80's with stuff like Jaws 3D, Halloween 3D, Amityville 3D and countless others... the 90's with the upsurge of IMAX 3D shorts and documentaries, and now here we are again, history repeating itself.