No one that exited before him was unlikeable
Liz might have been to some, but I generally found her personality positive and she didn't have OTTN edits.
Out of the seven castaways eliminated from the game -- more specifically the six eliminated by vote -- I count four as unlikeable (based upon what the audience saw).
Darnell: We barely got to know him, but he seemed likeable.
Jenny: She seemed likeable.
Liz: Her arrogance in believing that she could "manage" the rest of her tribe made her unlikeable. Maybe she was guilty by association with Peter. Yet her confessionals to the camera revealed this trait in her.
Caleb: Very likeable, certainly someone that audience wishes could have continued.
Alecia: Her immature ramblings made her unlikeable to anyone who conducts themselves like a self-respecting adult.
Anna: Although we did not see much of her until the episode in which see was eliminated, the content of her promotional video and profile on the CBS website combined with how she was willing to throw her only ally Tai under the bus revealed her to be the cunning, scheming type who felt she could read people better that the average person (based upon her poker-playing experience) and use her looks to make people go along with her. She deserved more time to prove her true personality to an audience, but based upon what we saw, she was rather unlikeable.
Peter: Like Liz, he arrogantly believed that he could "manage" his tribemates, and the petulance he displayed in the most recent episode (regarding seeking revenge against those who betrayed him) along with how he continually made narcissistic comments (according to those living with him at camp) made him quite unlikeable.
Out of the 11 remaining castaways, none can be unilaterally declared unlikeable yet, although we have seen, in varying degrees, certain traits in Jason, Nick, Joe, and Scot that could lead some to consider them unlikeable. For now, they deserve the benefit of the doubt. A lot of people found Debbie unlikeable in the first two episodes, but she has certainly proven herself to be rather likeable, despite her weird behavior, given her strong play in the game while simultaneous constructing good relationships. There is not much if anything to dislike about Julia, Michele, Cydney, Aubry, and Neal as of yet, but they seem to be the castaways who are best at keeping their personal thoughts to themselves. Tai is extremely likeable, whether you base it on personality or how he has played the game so far.