OK, so i finished the first game (the fan translation) while id agree the common route was rather long but i feel it was warranted. It has a large cast and the common route was needed set the seeds for the heroine routes as well as make the heroines likable so the player pick there own choice for waifu wars or arguments about best girl.
As for the reused comedy Gags and stereotypes, have you watched anime , read manga's or visual novels before? japan does this all the time other country's do this to varying degrees but japan seems to have perfected the art of it.