I would like to see more in the way of locations we can take the girls to on dates. Also I would love to see Lin reunited with her mom, and have her move into the hotel with Lin and the rest of the girls.
I like Vanessa, but surprised she is only a side character, she reminds me somewhat of maria (girl who does the web cam stuff). I think she should definitely be a main character, given how important she is in the scope of the story ie. Generally side characters don't have much in the way of content for a reason, which is the story focuses mostly on the main story, events and then the girls individually. Vanessa is far too important to left as a side character.
As mentioned elsewhere, shops, more locations , location , location to take the girls. It gives a sense of freedom to the game, and adds more immersion if done correctly.
More floors, and more girls need to be added to the main cast. I mean given that the hotel has what 5 main girls? I forget. Is this a hotel or a motel ;) I know we have the sanctuary bolted on, even that could and probably should be expanded. You haven't said much in the way about the elves going forward, but I am assuming your going to add more elven girls to the game?
One thing in these games that I don't like is the grind for money. I come home from work, to relax, play some harem hotel and other great games, and the last thing I want to do is even more work. I always use cheats to avoid the need for currency, I am not here to work, I am here for the girls stories etc. However I get that your going to have Lin's sister tend the farm automatically at some point.
Right now I can't honestly think of much more to write, because its very early in the morning and I am struggling to keep my eyes open.