Since you have certain releases already out from the planned 3.0 release list, would'nt it make sense to keep updating the docs, if not the libraries, regarding the changes to functions, their parameters and the changes to the json structures being returned.
e.g. I had build my code around 1.0, and with your 3.0 change, I have also started changing my code to be compatible to 3.0. However, I find that a simple call to "api.validate" in 3.0 that returns the user json, is different from the 1.0 return. e.g password_reset field is not there, spellings of exchange is changed to exchanges. Similar is is for product/s and order_type/s. Its difficult for us to "discover" such changes. Dont you agree a simple document explaining the new released features API level changes, would help us avoid these unnecessary trial and error fixes.
Right now we are rebuilding the documentation and client libraries. There are some breaking changes and some new features coming to the client libraries. It will be live shortly. Thank you for your patience.