Though I do acutally think that that's not the worst Idea. Once the main story and all important features are done, there's indeed quite a risk that the whole thing runs "out of steam" and will eventually be stopped, since one could see the game as somewhat completed. Yes, some story development is certainly needed from time to time but I personally wouldn't be sad to wait for let's say the prom/harem until all schoolgrils etc. are really properly done. It's of course a fine line to be drawn, but since there are basically two main stories, I'd say one should be left unfinished until the very end. Now we'll get the dad/family story with 0.20 and it looks like we'll get the prom with the dating system and this harem feature at the very, very end.
Tl;dr: I do actually prefer DC squeezing in content for stories, minor characters and other stuff from time to time, since I actually fear that this kind of content may never make it into the game afterwards.