I don’t dislike the character of Ahsoka per se, she’s a decently written character, though her hopeful idealism in Rebels got on my nerves (I hate overly idealistic characters in fiction, of which Rebels was overflowing with). What really annoys me about her is that her prescence and later continued existence makes no goddamn sense. She was Anakin’s Padawan and played a major role in many battles during the Clone Wars and against the Empire up until before the Battle of Yavin IV, yet she has NEVER been aknowledged in any of the live-action movies, and even worse, is revealed to still be alive in Rebels’ final season, plus she is shown to be interacting with practically every single major character in the SW franchise. At this point she’s like the elephant in the room.
IMO it would have been a lot better if Ahsoka had been introduced as the Padawan of one the many background Jedi Masters glimpsed in the prequels and have her story take place during the Clone Wars but removed from Anakin and Obi-Wan, fighting her own battles and occasionally crossing paths with Anakin and Obi-Wan. It would have expanded the Galaxy instead of having everyone knowing everyone.