She doesn't get enough credit because she's potrayed inaccurately from her other Type Moon/Fate related counterparts especially in F/SN. Going from F/SN to F/Z is such an off putting shift in an overall story because of such inconsistence in the story. https://twitter.com/Yung_Fetus/status/1303256760514301952

Saber would be fine and great character in a stand alone series, however she isn't. She's in a Sequel series towards a more ruthless and less honorable Saber from F/SN. The two Sabers are both potrayed differently, but F/SN's Saber is the original potray of the overall character.

Dislike of F/Z character comes from how the series is originally intended to be experience which is F/SN(all 3 routes) then F/Z, when done like this you'll start to see the inconsistences in her character and her actions at times within F/Z(The boring and passive parts).

The Banquet of Kings further proves this by having Saber listen to the words of Iskander which she herself would have never attended such a banquet in the first place nor let his words get to him. F/Z(anime atleast) doesn't go into the core reasonings behind Saber's Wish.

It was overall dealt better having Shirou talk to Saber because he understands her journey, but never regrets his actions. However he doesn't get through to her about her wish at this point, similar towards how the knights didn't get through to get about her questionable actions.

To sum up her potray in F/Z; She's a great character in the context of the series and it's theme overall, but poorly inconsistent to Type Moon as a whole.