About the X3 thing... the blame falls on many shoulders, but I really have to say that the LEAST of it goes to Ratner.
Fox wanted it rushed. BIG problem.
Singer got out to do Superman. Needs new director.
Matthew Vaughn (who, oddly, NEVER seems to get mentioned in these conversations) signs on, gets a fews week before filming.... and drops out citing that he wants to spend more time with his family. He came up with a number of key sequences, as well as cast Kelsey Grammer (inspired) and Vinnie Jones (ugh, just ugh).
So, then... with only weeks before Fox FORCED filming to start, Ratner signs on, gets very little script input, aside from moving the Golden Gate bridge sequence to the end. In essence, Ratner here was what Ratner always was... a competent, if deeply flawed, journeyman director. Let's look at Red Dragon... passable, but completely pedestrian and uninspired, which is what Ratner brings to films. What RD had that X3 didn't, was a good concept, script, and studio behind it.
So, yeah, honestly... Ratner is awful, but X3 honestly wasn't his fault. Most of the blame really goes to Fox & Tom Rothman, who forced a production to begin when it was nowhere near ready. The next biggest slice is, of course, to Bryan Singer. Once he left, it was Fox's baby, which killed it. Singer's goal was to focus on Dark Phoenix, it was Fox that pushed forward with the 'cure' storyline, and relegated Dark Phoenix (DARK
ing PHOENIX!) to an awful sidenote.
... it was an awful film, to be sure, but little of it was really Ratner's fault, sadly.