Kristina and Nick didn’t have a lasting connection. Did they get along? Did they have fun together? Sure. But their relationship never dove beneath surface level. By the time it came time to choose between Kristina and Corinne, it’s easy to see producers urging him in one specific blonde-haired direction because they didn’t want the show to lose its one big draw.
Kristina got the boot because she played the game wrong (and it is a game). She played honestly and with her feelings on the line. In the end, viewers (and apparently Nick) wanted a little less reality.