This is a fantastic start! How far do you plan on taking this?
Are you willing to share the code? I have some ideas and I'd like to see the internal architecture of the application so I can perhaps propose some changes.
I can't find my original post I made a long, long time ago, so I'll try to give you a basic idea of where I was going. My idea was based around a modding tool with version that would track the changes you made and had undo. When you got your mod to a place you liked it you could publish it which would at least produce a set of packaged raw files with a change log. However it would also be able to produce a simple plant/mineral/animal guide.
I've been editing and re-editing this email for at least 45 minutes now...*sigh*. Might as well mention a couple of those ideas now that I've had a while to think about it 
I was wonder about the option of a spreadsheet type view where, for example, each row of a datagridview is an object and each column is an attribute of the object. Then add some filtering options. For example, if one wanted to work on trees only, then they could bring up PLANTs in the grid view and filter down to only those have the TREE token.
Another thing I think would be handy is some sort of referential integrity. For example, if you changed the USE_MATERIAL_TEMPLATE on the Acacia tree to say "ACACIA" the Raw Explorer doesn't automatically re-point the BASIC_MAT to ACACIA, it's still "STRUCTURE".
Oh my it's quite late. I better stop now.
I don't really have any clear goals in mind for a place to stop, but I know that Raw Explorer isn't even close to being feature complete. I have plans for an entire plugin system that hasn't even been started yet. That system would allow anyone with .NET programming experience to write plugins for all the features you described and more!
I don't really have a problem releasing source code, but there are some things to keep in mind. It makes HEAVY use of the WinForms control library from
www.devexpress.com, which costs about $800 for a license. No one would be able to compile the application from source without having a valid license. That's a pretty big hurdle for most hobbiest programmers.
Your idea about recording changes is very similar to a feature I've been planning actually. Raw Explorer would record the steps you take with the ability to export those steps to a "diff file" that would allow anyone to play back those changes to a different set of raws. In effect allowing users to merge multiple mods together or apply mod changes to the base raws when a new version is released by Toady. Using it to generate a change log and other assorted user fields would be a fairly easy thing to add to that feature.
There is already a basic spreadsheet view similar to what you describe for materials until the tools menu. It's read only at the moment, but could be modified to allow changes to be bushed back to the library.
It would be great to hear any other ideas you have or that you come up with later. Like I've said in previous posts, I don't do any modding myself, so it's really hard for me to guess what type of tools would make things easier on you guys. Feedback and suggestions directly help to drive the features that Raw Explorer will get.