[TwilightsCall]

^ I would contest that statement.

Spoiler for just in case:

In Fate, Saber came to terms with the moral and emotional implications of her wish to replace herself with someone else as King of Britain, and ultimately decides against fulfilling her own wish - before she learns the grail is corrupted.

In UBW, Saber is basically towed along behind the story, comes in at the end where they notice the grail is corrupt, and takes up arms against it. She never has to face the implications of her wish as the chance at having it fulfilled is taken away before she is made to think about it.

There is very little character development for Saber in UBW or HF, whereas her development alongside Shirou is the main focus of Fate. The end result may be the same, in that her wish isn't granted in any of the three routes, but the only route in which she actually comes to terms with reality and accepts her fate and the fate of her kingdom, as it were, is in the Fate route. The same sort of thing "sort of" happens at the end of UBW, but it's really shoehorned in and feels almost like an afterthought, and I can't help but feel like it was just thrown in to take some of the tragedy out of Saber's disappearance rather than as an actual attempt at displaying character development.