The initial set of reviews seems underwhelming, which isn't exactly surprising. The Dark Phoenix saga really is too much to cram into one film, especially when we haven't really gotten to know Jean, Scott, etc. It would be like jumping into Infinity War and Endgame with just the Iron Man and Captain America movies coming before it. In some ways this has always been the problem with the X-Men movie franchise - they focus almost exclusively on a small number of people (Wolverine, Xavier, Magneto, Jennifer Lawrence Mystique), which really hurts when a film hinges on one of the other characters.
On the plus side, no matter how this ends at least it won't spend all of its time focusing on how much Logan is suffering. That automatically makes it better than the Last Stand.