Is there any development in the pipeline, to make Sonar more user friendly with Eucon protocol  and Avid Hardware?

Doubtful, since they are no longer developing the supported control surface stuff any longer. There is a user on here that goes by azslow3 who has been improving the control surface interface that Cakewalk open-sourced. At least, that's my understanding.
 
Here's the thread where he introduces it: http://forum.cakewalk.com/You-can-integrate-your-Control-Surface-with-SONAR-as-deep-as-you-want-m3125708.aspx
 
Regards,
Dan