Unoriginal. Family Guy have three main jokes-
The 'dragging out something so long its funny'.
The 'someone falling down very fast'.
And the 'Cutaway to something else'.
Lets deal with each of these seperately-
When the joke is dragged out so long, it gets tiresome. For instance I saw one when Stewie is taking the piss out of Brians unfinished novel for about a minute with Brian totally expressionless. When Stewie is finished, Brian punches him in the face. Now, if we wanted to see Stewie get punched, why didn't Brian just do it after about 10 seconds? The producers just waste time like this to try and hide the fact that they don't really have much of a storyline or other jokes.
The second one is the only aminatic trick that they really have. Its a good move, but the problem with Family Guy is that it can't stop at being amusing. It has to expoilt the trick so much that its just boring to see, and makes the show repetitive and unenjoyable. The first and the second are often combined to create double badness.
This one is my least favourite. Theres is a cutaway in pretty much every scene, and half the time it has little to do with the current subject. Most of the scenes end with 'like the time I' or 'this is worse than'. If they took these out of the program I think there would be about 10 minutes of very poorly written story.
Badly written/created characters. I'm going to take each one individually and write about why they suck-
Peter- He is basically a more exaggerated Homer Simpson. Don't get me wrong, FG kicks the crap out of the Simpsons, but this character is a blatant rip-off. They're both fat, lazy and stupid, and this isn't fair because like it or not, Homer was created first.
Lois- Has no real purpose. She's Peters wife, thats it.
Chris- Completely pointless. I've watched nearly all of season 5 and 6, and very little happens with him. He's hardly ever involved in the 'stories', I reckon he could be written out and it would make very little difference.
Meg- She's alright I suppose, but again little originality. I think the show would suffer without Meg, but they take her 'loserness' to the point of stupidity. If she isn't popular, ok, but her own parents don't know how old she is? Thats just ridiculous.
Brian- The only character I really don't hate, but he's still annoying. In the earlier seasons, he had some great jokes, but in the later ones he just sucks. He is the only one of the family who actually has a character, but like it or not, he's still monotonous and boring.
Stewie- When Stewie started off, he was pretty much a baby who was just wanted world domination. But now, he's basically a rather camp adult in a childs body. This shows that the show didn't think hard enough about what they wanted the characters to be like, therefore had to change the audiences favourite one to cover up the lack of ideas they had for him. He's written out of charcter is almost every episode, and ideas are taken from superior charcters- like Brian.
Trying to be offensive-
Family Guy use a lot of references which are clearly meant to offensive, but don't really work. For example, they make a lot of sex jokes. Now, for a program whose primary audience is 14-24 year olds how is a sex joke going to be even vaguely offensive? They try to offensive and 'off the wall', but they just need to be reminded that people over 40 don't watch the show therefore aren't going to give a shit. Deep down, I think they know this but attempt to model themselves after South Park anyway.
Lack of actual Storylines-
As I touched on earlier, Family Guy don't really have many actual stories. The episodes consist of a load of cutaways that don't have any relevance to the current situation. I'm positive there are episodes where more than half the characters don't even say a single line. The majority of FG stories in the later series are Brian and Stewie going off somewhere (completely ignoring the fact that Stewie is a baby and Brian is a dog) while the producers and writers can't be arsed with a sub-plot for the rest of them.
References to celebrities or pop-culture is not funny. For example, The Charlie and The Chocolate Factory factory. This episode fails on so many different levels, I had to stop half way through. I believe Futurama did a parody, but it was more imaginative and just used is as a basis for the writing, not copied it scene-for-scene like Family Guy did.
Heres a list of things Family Guy make fun of when theie own jokes have run out. Even if their own jokes were were funny (which they're not) they still revert to using popular things as props for comedy. Here we go-
Michael Jackson- at least 3 times
Charlie and the Chocolate Factory
Peanuts (Charlie Brown)- at least twice
Various American Celebrities no-one has heard of
Will and Grace
Friends (which admittedly is so bad, it deserve to be slaughtered)