All the episodes of any show will get 'dull' after a while.
The show will use any means possible to get some laughs.
What in the beginning of the show may have been a hahaha,
if the show goes on to long it will turn into a smile or not even a smile at all.
( Personally, I love family guy, even the latest episodes, that is just my kind of humor. )
Neither of any shows are bad/boring they are just made in a way that you need to love to understand, if you dont like family guy, you will problably like simpsons, if not, try south park etc.