My suspicion is that it's going to do very well even if, unlike the first two movies, it's a critical flop -- which I should note I'm not predicting. The last two movies did very well and the saga is going to have an awful lot of people who want to see how it officially ends regardless of whether they think TLJ (or TFA, for that matter) completely "worked." And J.J. Abrams certainly isn't likely to take the kind of story chances that Rian Johnson would, but he's also likely to make a leaner, less messy film, and might successfully thread the needle here. (I really hope the film doesn't try and pull off shocking twists to reverse the last film's shocking twists; it's always been in the back of my mind, though, that one of the story points some fans seemed to be so outraged about -- Rey being "a nobody" -- is a point that we technically only have Kylo Ren's word on.)
Having said all that, I don't think you're wrong -- I just think it's going to be the film after this year's that's going to be the real test!
Having said all that, I don't think you're wrong -- I just think it's going to be the film after this year's that's going to be the real test!