The original show was a gem as its stories were designed so that the seven characters "bounced off" one another in a way that highlighted their stereotype, cartoonish natures. The show was pure escapism - and it worked!
It was a gem of comedy.
With their removal from the island and separation from each other, the characters' took on a dull, blah realism as they had to interact with other characters and situations germane to their respective "real" environments. They no longer were funny. The magic of the series was missing due to this, and the show seemed more a weak drama with shallow, predictable plots and a few strained comedic interludes.
While it initially was nice to see the characters again, I prefer to remember them as they originally were intended to be.