Are you sure you didn't mean Jill there?
Nope. I meant Claire
Jill's face has changed multiple times. The only time she's look similar was in RE and RE3. Actually... most of the characters have changed their looks with each game, more or less with each generation of consoles. I am a fan of Jill's face in Revelations, it doesn't both me. The important thing is that her personality remained the same. It was only in RE5 that she was out of place imho. After she broke free from her mind control, I found her flirty remarks to be very out of character for her.
As for Claire. She rubbed off as a different character in all the games to me. Only RE2 and CVX did she remain constant. She was unique and likable. A badass rock star like biker chick in RE2. She was there looking for her brother, that story continued in CVX. In Degeneration, she was this very soft woman and her hardness was worn off. In Revelations 2 she a very static character, actually she was the only static character in the game. It was like she was there.... just to be there and Capcom didn't bother to develop her. She was pretty much there for fan service and not for a story telling point of view. It was Moira who's story was really being told in those episodes. I can't even really tell you what kind of personality she had in that game.
I could tell you that
Moira was a punk with daddy, and likely authority issues. She was fearful of guns and harming others based on past events. She was very good with children and was able to keep her vulgar mouth shut around them. Very caring and she came to regret all her anger and hurt when death was approaching. It took the worst to bring out the best of her. I love her personality and I think her and I would be best friends irl xD
Natalia was this young naïve girl who had no idea what was going on around her. She is very trusting of men and only sees the good in them. She trusted both Neil and Barry without any questions asked and felt comfortable and save around them. She even referred to the backstabbing asswipe Neil as "The good man". Natalia holds a sense of fear and distrust toward women. She flee'd from both Claire and Moira when she first met them and Moira had to comfort her and even called her a sister in the terms of them being in the same situation (great foreshadowing for the end). You cannot blame Natalia for feeling this way after what Alex did to her. Very horrific acts and it's suggested that she did very cruel experiments on her. She both physically and emotionally abused her throughout the game.
Barry still remains the family man. He is father who was guilt ridden with failure due to a mistake he made in the past that caused Moira to hate him. He loves his daughters and would give anything to fix those wrongs. His daughter went kidnapped and he spent 6 months of doing nothing but searching for her around the globe, finally tracing a clue to her whereabouts. He met Natalia and saved her, eventually recognising her as a daughter and adopting her. This gives him a second chance of being a father giving him to be the man he always wanted to be. To fix where he went wrong. The bad ending was very tragic because Alex did the worst possible thing you could do to Barry. His daughter is dead, the girl he tried to save is dead (her conscious left and she died when Alex crushed her. Essentially her soul left her body) She could have killed Barry but instead she left him there to live with his guilt of being a failure and a bad father for the rest of his life. With no escape or way off the island (Claire returned with the BSAA as back up. The boat that found her likely had the co-ordinates) all Barry could do is crawl up in a corner and living with his regrets for the rest of his life. He likely would lose the will to live and die on his own terms. This is very good story writing in my opinion. My god.... Alex is a bitch who gets no salvation, she's literally worse than the devil if she isn't the devil.
In the end, never **** with Barry's family or he's coming for you. Also the word "Wesker" is probably the most offensive word to him. He's a family man and this trait that defines him grows and expands as the story goes on in very dynamic ways.
I'm not going to go into Alex because I would write a 5 page essay on her personality and motivations. Sorry, but **** this to the moon and back. I've done it multiple times. I'll just say she's a very philosophical and complex character. The most complicated character in the series by a long shot.
As for Claire... I can't answer that question. She was in the game because.... well I don't know.
Consistent appearance ≠ consistent personality