Sadly the remaster and remake order for their games is all the way fucked up. Rance 2 was remastered in 2010, after that Rance 1 had a full remake with new characters and a new system, then they skipped actually giving Rance 2 a proper remake and went right on with remaking Rance 3, even giving that game voice acting as the only one in the series. Now the next logical game to remake would be 4, but as far as I know there are no plans for it, though I haven't made a deeper check for years now so who knows. After 4 theres 5D which isn't even a full game, and 6 which is a full game, so no idea how they could approach that in a sensible way if they were to remake them in order.
Funnily enough since the order and differing states of the games are already so screwed up, they could actually get away with just remaking or remastering Sengoku Rance without considering the games in between, which I think they should have done to give people like me who have played it many years ago in english an actual reason to buy and replay it. But well, seems like theres enough people buying it unchanged anyway, so I guess it would be stupid of them to even bother and put in the effort if they get money regardless.