To use another game as an example, you shouldn't be worried that the side characters will have small amounts of plot and faster corruption scenes. It sounds like Fujino is slipping into the same thought process as N_Taii, ntr dev of Henteria Chronicles. They do the same. Have side characters on a faster corruption route to keep the player engaged, while the Main Characters corruption route stretches out longer.
It's just that in part 1 those side characters were just one-off's and cameo's, now they're going to have mini storylines, fast corruption and sex scenes so players get to see lewds even if Inoda has to take the long route back to corrupting Asuna more.