Their current biggest problem is that they have anything you can search for, so if you want to stream something for free, their search isn't that useful since it throws off false positives for a ton of stuff that you'd have to rent or buy.
Netflix wants to be mega-sized HBO, but having that much original content under one umbrella seems to be straining them - the signal-to-noise ratio is low, and I can't be bothered to sift through the number of originals they put out these days to find the interesting ones. Sub-channels that operate more independently to build individual reputations for genres or themes seems like a much better model.
Vue, Sling, DirecTV Now are hobbled by the fact that they're tied to the same original source restrictions as traditional cable, so you get commercials, "edited for content" versions of movies, and all that nonsense. Too many layers of indirection between them and the content makers.
Hulu has a good thing going with their own originals + HBO/Showtime add-ons, but their live TV offering seems like a confused step backward, since if you add that it introduces all of the above problems to part of the library. Soon you end up in the same place as Amazon's current problem of search being too cluttered with the wrong stuff.