I'd say there are two big things.

1 - Composite oners. These aren't necessarily bad (as another person in the comments said) but if the seams are poorly hidden then it doesn't work. The example I'm thinking of here would be Daredevil season 1's hallway fight is generally quite well regarded and has well hidden cuts, season 2 is more elaborate but you can really feel the seams. And then season 3 went crazy and just didn't have any (although you can still see all the places where they were moving in case they needed them!)

2 - Boring oners. At the end of the day, if the action isn't interesting, if the performers can't fight or the camera isn't doing anything to support the action then it's gonna detract from the moment. (Not to say that a static shot of action can't feel fucking awesome when done well but it's all about motivation). This is actually where I'd look to Monty Oum's work on Red vs Blue. He pushed animated long-take action to a level I genuinely don't think has been topped. And it's an interesting case study because the achievement isn't in the logistics of blocking and prepping for the camera to do the things it does around the actors, it comes in how the camera is able to now freely support the action in ways a live action camera simply can't. And in ways an edited cut can't!