I understand that you want/need to make money of the game somehow but I'm not sure that removing existing features is the best way to go. One suggestion is to limit some of the upcoming scenes to those who've purchased the game, or are supporting you on Patreon.
Maybe make the free scenes shorter, and the premium scenes longer, perhaps with multiple positions, additional oral/anal, or similar.
Maybe introduce a completely new girl that is in the free game, but without any sex scenes - those are only available in the premium version.
Finally, I've already purchased the game - do I have to buy it again to unlock replays if you move forward with this change?