By the sounds of it, they aren't going to go and wholesale change the class (IE, anything that invalidates the PHB) so I don't expect wild departures like a spell-less variant or the original Ranger test they floated with the ghost-puppers.
So what can they do to fix the class?
They could design some meatier new sublclasses that replace the current crop. There is already some power disparity between the PHB subs and the Xanathar ones (bonus spells being an example) but that does little fix the main class problems like Favored Terrain or Favored Enemy. Also, some of those newer Xanathar subs are sweet, and hunter is generally liked.
They could likewise add more spells and combat styles, but I fail to see those move the needle and many of those abilities end up shared with other classes anyway.
They could offer alternative class features, but I'm 90% certain that anything that comes out will be better than the PHB options so its functionally optional Errata.
They could, also, just errata the class features to beef those up more. However, that runs into the traditional problem with errata.
Finally, they could just add a new subsystem that plays nice with the ranger (such as a proper animal companion rule not tied to familiars or Beastmaster) but again, that doesn't fix the problem with rangers per se and instead is just a band-aid.
I dunno, any other ideas?