Random comments/advice. Hopefully vaguely constructive:

• You don't actually say what your module does anywhere in the introduction :-)
• Stick to something close to the POD outline structure generated by h2xs, Module::Starter and similar. In particular:
  1. The NAME section should give a one line summary of what the module does
  2. The SYNOPSIS section should give a short end-to-end code example of the module working. Use comments to explain what's happening.
  3. The DESCRIPTION should supply a brief text description of what the module does
  Basically - if I don't have a good idea of what a module does by the second paragraph of the description I usually stop reading.
• Code beats text. Don't talk about concepts if you can demonstrate them with code. Currently you have to read about half the document before you get something close to a real-world code example.
• Aim the main module documentation at a reader who understands the concepts involved. If you need to teach or preach move it to separate documents. It gets in the way of people trying to use the main module documentation for reference.
• If there are modules on CPAN that do vaguely similar things (and these days when is this ever not the case :-) include a compare and contrast section. Show where your module is better and worse than the alternatives.
• Always have a "Why" for your "What". When you're explaining what a particular piece of API does, explain why you would want it to work in that way. For example when I originally wrote the description for startup and shutdown methods in Test::Class I didn't have the DBI example. I added it later because it makes it much more obvious why using that particular feature can be a good idea.
• Tree::Model doesn't tell me anything about what the module does apart from the fact is presumably has something to do with modelling trees?

(and before anybody points it out - yes I should follow more of my own advice with some of my modules :-)