The bathroom humor of "Married...", as far as I'm concerned, was always secondary. Yes, it would come up fairly regularly in isolated bits & jokes, but there were very few episodes that focused on it. "Luck Of The Bundys", for example, focuses on "The Bundy Curse", which states that, for any good luck that arises for a Bundy, an equal & opposite amount of bad luck will be accumulated (& none of it has to do with the toilet)--
"Beavis & Butthead" could certainly be said to be guiltier of bathroom humor than "Married...", but it, too, isn't given enough credit for the (admittedly less common) subtler side of its humor.
"South Park" is also a classic.