I think this is a good idea... though I would also think that each -writeup- should be a part of the nodesphere, not necessarily the E2node itself. For example, with the node magic, for example, there can be several different nodespheres... one for stage magic, one for magic: the addiction, one as a crosslink into magick (as a common misspelling), one into AD&D and other roleplaying games, one into operating systems (magic numbers in structures, for example), and undoubtedly many other concepts that I'm not even thinking of.
The main problem is that users are going to want to follow their trains of thought on each topic, not just each title. So the question becomes one of confusion... how can I create multiple writeups under a given node, with all attributes except text and nodesphere being the same? Or, how can I assign my writeup to multiple nodespheres?
Should nodesphere creation be a function of higher-level noders? Should nodesphere contribution be a function of level 3 or so (low-level enough that users can gain experience through the contributions, but high-level enough to weed out the trolls)? Would the person who created the nodesphere have editorial say as to the contents of the nodesphere that was created, and would s/he be able to delegate some of the nodesphere editor's powers? How would it look on the back end -- what dbtables would need to be modified, and what kind of code would be needed to support it?