I think they struggled with making the characters is 3D characters in the early 90s, and not just a "a cop" or "a teacher". Nick, Luke, Grant and Roxy were mainly cast as their occupation and on the flip side Lou and Ben were purely a vehicle for family dramas with limited connection to anyone outside of 2 -3 characters. This meant to an extent they only served one purpose or could work well with one age group of characters, limiting their storylines. When the show moved into the mid-late 90s with Travis, Stevo v2, Kelly and later Sally, Shauna, Harry and Vinnie we see these characters could have scenes with all ages and groupings of characters, whether it was socially or through their work.