As a relatively new-comer to DNN been working with it for over 2 years, I am concerned that now with Google penalising for speed. That DNN hasnt been able to address the combining css and js scripts. I know there is snapsis However even on their site google reports an error with performance saying JS needs to be combined. My question is to the DNN seeing as the DNN homepage results in a google performance rating of 67, joomla 77, umbraco 81 and wordpress 90. Will impending release of 5.5 go as far to take performance into consideration?

You could look at this: http://ultimateskinobject.codeplex.com/   It would allow you to make your own combined and optimized CSS and JS files to replace the core ones.

No this doesn't and Pageblaster is certainly great for most installations.  However, this would allow you to control the merge/minifiy process and have IIS handle compression and caching.