Hi Dam,
Since, in my opinion, OS Calendar expands OS Property to opportunities to work with the hotels, I would like to see in the future, the following features:
1. I am shocked, but the room is only one picture, for that so? I am sure that for you it is very easy to make a gallery for rooms.
2. Description of facilities by groups to rooms
2.1 Opportunity to present facilities using icons, pictures or fonts, I know that it's not easy, but I hope you will find a solution!
2.2 Add some field type, as image, url...
2.3 Filtering by fields
3. Deposits by rooms fixed amount or percentage, related with price by availability.
So far there is so much.
Thanks for your work and attention!