I do agree that the show has a feel of Seth MacFarlane nowadays, but it's not like the show wasn't trying to find that feel. Remember when the show was facing the first of it's decline? Family Guy that was the brand new show at that time took over and made the bigger numbers. For a while, the show was competing with what it had, but then they started using a little of their formula to become the best animated show.
I am not a regular American Dad! watcher and haven't seen all the episodes, but I never found Stan to be the most sympathetic character on the show. He is a huge moron that doesn't care about his family anymore and could easily be compared to Peter Griffin. Every family member on the Smith family is a literal clone of the Griffin family members. I will demonstrate:
Peter Griffin - Stan Smith: They both can be huge jerks to their families, are pretty moronic, have almost no compassion left for any being in their universe and generally like to play the victim.
Lois Griffin - Francine Smith: They are both housewives, good fighters and like to play "dirty" at times.
Klaus - Meg Griffin: They are obviously both the poorly-treated characters, they don't get any respect from the other family members, they don't get enough character development and need to be accompanied by another character because of it (Meg + Brian, Peter or Chris/ Klaus + Steve, Stan, Francine or Roger) and don't have a lot of things to do anymore than being the living, walking joke of the show.
Steve Smith - Chris Griffin: They are both weird, isolated characters that don't have a lot of friends, are social outcasts and deliver some pretty bad jokes (Not really Steve, but Chris does most of the time nowadays. I mean what is the purpose of his character anymore? At least Meg is the punching bag!).
Roger Smith + Stewie Griffin: Both of them are secret geniuses, the LGBTQ+ characters of the show (I am not really sure about Roger anymore, but I think they concluded that Stewie is LGBTQ+ in one of Seth MacFarlane's interviews) and are both very dangerous for the public.
Hayley Smith + Brian Griffin: Both are atheists, liberals, ate very opinionated and are generally considered slackers (Not so much Brian, but Hayley is).
Everyone is a direct copy of the older character, as a result of laziness on the writers' part. I don't see much of a difference between the characters from Family Guy and American Dad!
So, I don't see how Stan is more sympathetic than Peter. They are the same person, so shouldn't Peter be viewed as sympathetic too? He is always in the wrong too so why not?
If I had to pick the most sympathetic character nowadays, it would probably be Francine. She is always trying her best to be a good mother, acknowledges her mistakes, tries to learn from and in the end, she receives her own punishment. I did compare her to Lois Griffin, but they are not so alike. At least Francine doesn't exclude or blame her own daughter for her unhappiness nor does she not show love and care to her children.
I don't understand you point of view. There are so many animated shows that do the exact same thing. If anything, Family Guy and American Dad! are the show s that are more plot oriented, even more than The Cleveland Show.
This is not the only character trait of Marge. Why is everyone always complaining about Marge? What is so bad about Marge? Like all the characters, she has changed. If anything, I find Marge to be one of the most sympathetic characters of the show nowadays.
Yes, she does play the victim sometimes when it's not her moment, but this is often due to the poor writing choices. There are some moments where they acknowledge it and some others that don't, that's my biggest problem with "Steal This Episode". It characterises Marge so poorly that I do wonder why people think it is such a good episode!
It is the same, old TV trope in almost all TV series. The men are dumb, oblivious and self-centered while the women are smart, beautiful and don't do anything wrong. I don't take it as a big issue that they don't acknowledge Lisa's or Marge's flaws, I have come accept it. It does bug me at times, but it's not my biggest issue with the show's characters.
My biggest issue with Lisa is that the writers don't seem to want to give her a moment where she realises that not everyone will love, appreciate and agree with you. I know that she is only 8 and that this might seem pretty deep for her, but I think it is important for her character progression to accept it. Not everyone will like you in your life, that's why we have to be strong to defend ourselves in this cruel world.
Yes, the writers do seem to like writing Bart as the "bad boy" of almost every situation he is in, especially when Lisa is involved. I do think it's unfair, but there are times where he really deserves what he gets.
Homer was always meant to be the every man of the show. He could either be the hero of the episode or the Bad Guy of it. The difference is that the show knew when Homer was either of these things and didn't just put him in a situation and labeled him as "Hero" or "Villain" of the story. There are times where it is understandable and I can buy it ("I Am Dancing As Fat As I Can", "Heartbreak Hotel" etc.) and some other that I don't.