To me what you are describing moves away from the relaxed, informal approach to the Treehouse live stream which is a part of why it was so successful. I wouldn't want Nintendo to add any pomp or smoke or lights to the format. I think it would be cool for the live stream to have some surprises but adding audience seating and things like that start to get into press conference territory where they are performing for a live audience. Also I don't think Nintendo wants people to crowd their booth just to watch an event instead of getting hands on with the games.
So much this.
It's why I think Nintendo was so successful and why other outlets that already have similar formats haven't resonated with people as much as this stream.
The Treehouse were having fun. When they were at ease, it made others feel at ease. You can tell the difference between developers coming there prepared to present something and developers that just wanted to play and talk about the game. Even with some Nintendo developers, things were more formal at times but when they had say the Splatoon devs playing against the Treehouse, everyone is just there to have fun and it was awesome.
Seeing Treehouse members show off games they had been working on was more like a friend showing off their favorite game they had been playing rather than a presentation introducing a game to a new audience or a reviewer playing a game for the first time.
That more casual but informative format is what made it great. Even when Reggie would stop by, it was just to hang out and talk, and while some people seemed to get upset that he wouldn't be there to announce anything, I think people such as myself appreciated that he got to take off his COO hat for a while and just be there as an observer.
This was refreshing because it was so genuine. The more they try to "capitalize" on the positive reaction could take away from that. If Nintendo expands on the idea, I hope they don't forget that people didn't just like it because the platform was new, but because their whole take on interacting with the fans was different. It was uniquely Nintendo in it's approach.
I don't ever want Nintendo to be like everyone else. I want them to be the best Nintendo they can be at all times, because that is what got them this far and that is what has kept me as a fan.