I really like how the Dark Dreams (BDSM) story was done, especially attention to detail during the BDSM scene. It's probably the only truly interactive bondage scene I've actually seen in a sex game (I probably spent the first 30 minutes of that scene trying to see how many different ways I could pose Samantha, using boxes and whatever else to play round with the physics engine. lol).I know there's a lot of other work that probably takes priority at the moment, but it would be great to see some more bondage and BDSM expansion.
For instance might be pretty cool if the player was able to interactively bind and pose a girl somehow. Maybe using something like anchor points you can "tie" and "attach" to connect different points on rope or leather cuffs, making it so you can put her in all kinds of different positions, depending on basically how you tied her up.
Another idea might be to make it so the rope/leather could be manipulated by the player and adjusted, much like how the clothing system currently works, so you can adjust the rope/leather strap's position to get different results. Like say, sliding a rope loop up her ankles and around her thighs. If that makes any sense. Could be easier to do than a complex "anchor" system, and it would be great for breast bondage and crotch-ties.
More toys and bondage gear would be nice too of course, but I figured it wasn't really worth mentioning much since you guys probably already have some plans there.

Edit: I'm not sure if my description was very clear, so if there's any confusion as to... what the hell I'm talking about, please feel free to say something.