I'd say that Silver Island was underwhelming. An okay idea, with not-so-good execution.
- The "advance tickets" idea, I'm fine with. Keep that.
- Starting the events at 8pm felt weird. Especially for the screening rooms.
Eh I don't mind the start time besides it conflicting with other events.
- Night Market: you can go to Artists Alley and get a similar, if not the same, effect. It didn't even have a Fakku booth XD
That was my take as well. I was expecting 20 inch Dragon Dildos and got Artist Alley with some nipple slip
- Casino Night looked cool at least. The table games seemed to be more Vegas casino style rather than Indian casino style.
- Adult Game Room: meh.
- Didn't bother watching the stage shows. No further comment.
I didnt check any of those out other then passing by them. Didnt even know where the Adult Gaming Room was.
- The HMV show was run just fine...but something about the line for it, I didn't like...
Didnt get to go, our driver was too lazy to get into the car and we were going to stand in the shuttle line.
The general hentai video rooms were easy to get into. No real complaint on the setup except perhaps the rooms being too small for larger scale events.
Overall, I say bring the Hentai events back to "the mainland." Take back the Marriott rooms, lol. But what should take its place at the DoubleTree, you ask? 
I agree. It isnt like they segregated the 18+ panels that were just Hentai Video Rooms with commentary. What did they even use the Marriott rooms for this year?
The DoubleTree just cant host any large events given the distance and its apparent capacity. Odd events are fine (perfect location for the JoJo Escape room last year, as an example), and perhaps the Casino setup they had was alright too. Don't know what they could shift over there though. The Manga Lounge? Artist Exhibit (if they are still doing that)?