There are alot of problems with Season 4. And all of these problems are due to the writing staff, who did a horrible job of formating the show. First of all, as people said before, they move way too fast, with miminal humor, most of the episode is just fluff. The previous seasons had genuine humor along with a good plot. The episodes now move way to fast, and its over before it started.
The minimal humor they have isn't paletable to all audiences, it targets only the younger crowd, while former seasons were entertaining for people of all ages. For example, Patrick was a great character, but now, his dialouge is weak, and the rare moments he has aren't even comparible to before. Also, His main characteristic, which, to me and many other people made him funny, his stupidity is repeatidy either over or under used. I don't see Season 5 being any better. It seems the end for the classic Spongebob we all enjoy.