This excuse worked back when this game started.Oni is, was, and probably always will be an artist first and a coder second. Expecting more complexity from the game systems with Oni as sole dev is on par with expecting Forrest Gump to give up shrimping and go get a Phd... not saying it's impossible, but definitely improbable. Maybe one of the mods for the game will do this eventually, but none of them really seem concerned with it. Oni more likely to just keep drawing ladies, so maybe we get Wanda by 2028?
This is a project that gets more funding than most commercial games. He makes over 60k a year from this and has no expenses other than his personal ones.
He could easily afford to hire someone professional to go over simple renpy code at least once every iteration. Rogue-like is not a complex game. It doesn't need someone working full time.
Personally, I bought the excuse of "pride" that he gave years ago and how he wants the game to be "his project". But now we are over 6 years down the line and I just think it is greed at this point.