A few opinions, if I may:
-Please don't "burn the world down". A lot of work has been done obtaining colored wool and constructing things lately. I'd really hate to see hours and hours of hard work gone up in smoke because someone wanted to have a little fun. If you want to destroy something, please build it yourself first.
-I'm not totally against the TNT demolition idea... However I don't think that it should take place in the main world specifically for scenic purposes. Perhaps an alternate world where the demolitionists could go frolic?
-Space world is totally useless in it's current iteration. There's nothing out there to explore, therefore no incentive to build. (even if the game would let you build out there) Wearing a pumpkin helmet is ridiculous, especially since it obstructs one's field of vision. I suppose that could be corrected within a texture pack. Honestly, I think Sphere Dimension is more "space-like" than the Space realm. There is more of an incentive to explore these already established worlds, and it looks pretty damn cool.
-On the subject of Sphere world.. I think if you guys want to claim a sphere, it would be best to label it with a sign on the entrance. Most people already do. But if you're going to stake a claim on a world, then make something out of it! I believe that if a sphere hasn't been claimed, then it is fair game to plunder its resources.
-Hopefully Adventure World will serve some purpose in the near future... If not, then we don't need it.
-Also, DDR. There are still some issues with breaking glass on certain spheres. Specifically, the smaller ones. We get a message that the glass is protected and can only be broken by an OP. I'd hate to have to trouble you to break glass on a new planet every-so-often..