One of the best things about TWOK is how much Kirk has changed as he reaches his midlife crisis. Were he the same James Kirk who marooned Khan and his followers on Ceti Alpha V then it wouldn't be half as interesting a movie.
Guinan A meets Picard in 1893, a man from Earth's future, one that gives her hope for the species future, which makes the road she travels a little more bearable.
Guinan B doesn't meet the man from the future. Watches as humanity continues to make the same mistakes over and over thus becoming jaded about the prospects of humanity.
I can see the reasoning around her portrayal in the current story.