I recently just watched all of family guy in reverse order. It started out as, I couldn't be bothered to figure out which episodes I had seen tireless reruns of so I just started at the latest... then I had nothing better to do and went down to episode one.
The show was definitely worse at the beginning- I love the newer episodes- hilarious and entertaining. At some point around season 3 I only kept watching for the sake completion. I will say that I dislike Brian's new persona to the extent that I might think his bland "father knows best" persona of season one was preferable, however I can't deny that the best episodes tend to be the ones centered around he and stewie. So I guess I just dislike episodes *about* brian (finding love, going to college, etc), but think he makes a fantastic team with stewie.
Regarding Futurama, it definitely isn't a holy grail of any kind. Let it be known that I really love the show- it's intelligent, funny, and very subtle. Its appeal isn't something that would be immediately perceptible. At least that was true of the earlier seasons- I don't catalog in which season I think each show starts to decline, but I can tell you that the decline is largely related to the huge change in Bender's character. I can't really describe what he used to be, but now he's just a generic jerk with predictable, unfunny commentary, only occasionally remembering that he has some half assed emotional development when it's built into the ep's plot.
Last season definitely had *something* wrong with it even if I can't articulate what it was. The inconsistency of Fry and Leela's relationship is particularly annoying though- it's as if the writers are trying to have their cake and eat it too. While they're technically "together", one of two things happens in each episode: 1) Leela is on the verge of breaking up with Fry and treating him like she treated him when they weren't an item. 2) The episode plays out with no reference to their relationship at all, as if they weren't dating. At least two of my friends think that "futurama isn't as good now that Fry and Leela are together, like what happened with The Office". Except for all intents and purposes, they aren't even together. Seems like the writers are trying to please two different crowds and failing at both.
This final season isn't *bad* so far, but it feels like tribute after tribute to all the memes the show has generated (self aware in a bad way), and I wouldn't recommend any of the episodes to someone just getting into the show. A good time to end I think.