One of the problems we have with feature suggestions is the vagueness of many suggestions - the filed suggestion says little more than "make a scene graph feature", which means it's pretty much left entirely up to our interpretation of that. We have some rough plans, but our job is to make what users want. The risk of a vague suggestion is we do what we think was meant, but really people were thinking of something else. I try to encourage people to be detailed and comprehensive but often that doesn't happen.
If you think the scene graph should work in a particular way, now is definitely the time to explain what you think that should mean, in detail. Screenshot mockups, comparing various approaches, thinking about advantages/disadvantages and tradeoffs, the various editing facilities, the runtime features, the edge cases that might trip people up, how it might tie in to other existing features and potential future ones... all of that is important and can result in significant delays if it's not properly thought through in advance. You don't have to do any of this - if nobody does, as I mentioned we'll just do our own interpretation of it - but if you have strong feelings about how it ought to work, the sooner you provide a comprehensive and clear explanation of what that is, the better chance we have of incorporating that.