He obviously likes the fetish of chichi getting fucked by her old neighbor, i honestly don't care, as long as i can see chichi's ass getting fucked (in a good scene) i don't care by who, but as far as the game concept goes, this isn't called "chchi's wild adventures" and i understand why this can make people upset.
But i also think this is easly fixeable, he just has to make Roshi content and let the girls perspective as side conent. Just make a questline about a girl (a questline where you HAVE to play with Roshi) and that questline ends with Roshi fucking the girl in question, then that girl is unlocked as playable character and you can have content for her where she has sex with other people (maybe 18 has to fuck Hercule to get money from him, maybe Panchy goes to the store in west city and she's gangbanged by thugs, idk the possibilities are endless) and then you can go to the next girl, and the game ends when roshi sleeps with idk, six girls maybe (chichi, bulma, 18, videl, launch, panchy) then you do a congratulation scene or drawing with king of harem Roshi and that's it. It's basic as fuck sure but i also think it's efficient, you have your main character, main "story" while also having the posibility to deviate from said story to explore the girls (or other weirdos like oolong) POV if you are into that.
this is how i would do it at least, but i'm not a supporter so i really don't mind even if this game gets incomplete eventually, as long as it has good sex scenes every update i'm fine, but if you are a supporter and want to see the game finished i think you should let him know the problems you have with the current state of development