Two features that I feel are really missing from the game:
#1 - Once your relationship is high enough with a particular girl, the player should have sex options after their date (eating, TV, beach, etc.). This almost never occurs. I don't know about everyone else, but after I took my girlfriend out on a date we went to my place or hers and at least made out and cuddled for a while (often times we got naked and had sex). It just feels unnatural to have such a close relationship with a particular girl and end your date with no physical intimacy of any kind (not even a kiss most of the time).
#2 - The option to invite a particular girl (whom you have an excellent relationship with) to sleep with you at night. This only occurs a couple of times in game.
These options would make the game feel a lot more personal as well as realistic.
I'll probably wrap up all of these comments into a full review at some point but these are my impressions of the game so far. Overall it is a great game!