I do always have an issue when people make a review about a game or tv show or film or book or comic book or graphic novel, they write or say for example:
"this A game has likeable characters so it's good" or "This B animated show has dislikeable characters therefore it's bad".
With these examples, that's where my problems resides, a quality of a story doesn't reside if the characters are likeable or not, because people have different opinions on what they consider likeable or not, it's quite like in Harry Potter books and movies, each person who read the books has a different vision of the characters, so of course the actors wouldn't be like exactly or very similar to the character as the readers had in their minds, so the right way to evaluate a character is by analysing and see how well-rounded they are, not if likeable or not.
The purpose of well-rounded characters, it's not with the intention to make the character likeable or glorified or to be a role model but to treat as a person first with flaws, virtues, strengths, weaknesses, vulnerabilities, the amount of resilience, convictions, ideals, not a black-white character but much deeper and complex, more to the character than what meets the surface.
Many people has the bad habit of judging a character or evaluate them basing on what's on the surface of their actions, don't even question why he/she did, when given reasons is:
"because he is a jerk" or "because she is annoying" (each person has a different ideas of what they consider annoying or jerk) and when they say why they think a character is annoying or jerk:
"because it did A,B,C,D,etc.", but the actions/reactions/personality traits and why he/she did it, that's what a well-rounded character is. Remember Understanding is different from Liking, understanding a character doesn't mean you like the character.
It's noticeable likeable and dislikeable is a matter of a personal subjective opinion and not an evaluation.
If the characters are well-rounded or not, it's an evaluation.
there is many well-rounded characters I dislike, Umbridge, Voldemort, Amon, Lucius Malfoy, "Father" Homunculus, etc.
as much there is many well-rounded characters I like and love, Atemu/Atem"Yami No Yugi", Yugi Mutou, Harry Potter, Izayoi Aki, Hermione Granger, Ron Weasley, Azula, Aqua, etc...(yeah, too many to list).
also there are few well-rounded characters which I feel indifferent or like and dislike, Snape (sorry fans, but he is in my like and dislike list, in another words, in the middle :p), Mazaki Anzu (same with Snape), most of the Homunculus, etc.
I hope I was clear :).