With a play, every night is a second take!! It's true, you don't get a re-do. If you mess up in front of the audience you just have to soldier on (I know this having been in many plays). If anything that would make it more in the spirit of a 'single take' not less in my view. Besides, looking at it that way, each consecutive performance could be viewed, in essence, as another take.
Sure the 90-minute one take thing is a gimmick - as are adventures in space, transformers, surprise endings, 3D, computer animation, etc. - all kinds of things if you want to look at it that way - doesn't mean the film's no good. In fact one of the reasons 'gimmicks' can stand out is if the film is well done despite the fact that it was shot in one take.
I mean, if I saw this film and loved it and it was ALSO all done in one take, I'd be impressed and would certainly mention that fact when discussing it with others.
Again, though, I haven't seen this particular movie.