the first version of the framework was first released in 2007, recently we entirely re-wrote the framework and released in 2010 as version 2.0. The Rain Framework is basically new and we're still working to make it better, that's why some classes are coupled differently. Soon we will release Rain CMS http://www.raincms.com and Rain TPL 3, in alpha version on github https://github.com/rainphp/raintpl3 and the next step it will be the Rain Framework 3.0.
Thanks for your positive feedback, in particular thanks for your critic, because help us to do better!
You are also invited to contribute on the rainframework code, github it's very easy and fun: