I replayed the update with the new adjustments. I think they fixed the tone issue, mostly, on the Vicky Sis scene. I was never bothered by it happening, but rather by the fact that Vicky was way more possessive of MC than any previous interaction with her had led us to believe, despite her acknowledging that MC was given a free pass by his GF. The Twins route is still way messier than it needed to be, but I am fine with it except it really should have had a third choice between MC fully on board or fully off, but I understand that would make more work and more coding for little payoff.
What the Dot's team should have done is made the initial choice of open relationship or end it with MC's girlfriend, the demarcation line. If you choose to end it, you get the most vanilla route, where nobody ever has sex anywhere or any time without MC. Basically, all the "no NTR" folks could have their safe space where the only sex is with MC and nobody ever has a sexual thought unless they are in his presence. On that route, Sis and Vic are friends. The twins run a party business. There are no plot twists, just vanilla story. If you choose to have the open relationship (something the no NTR brigade would never, ever choose) you can introduce the sis/Vic relationship and any of the other plot twists. I think it would have cut down on the whining some, at least, though some would probably complain about a route for existing, even if they were not playing it.