Bandam Srinivas Reddy

An interesting and challenging question indeed… There are two, rather three parts in this Question.
 
Is a process as a significant roadblock in the effort towards creative design work? There are many innovations that happened purely by accident !!! Is there any value in the use of Lean Six Sigma in the world of product innovation?  
To answer the second one first:
I tend to agree that there are/were many innovations that happened purely by accident.
Sometimes genius arrives by chance and not by choice. 
 
Examples are many including Coco-cola, Cornflakes, Microwave Oven, X-rays, Pacemaker and the list would go on. Another example close to my family, redbus.com, online bus ticketing portal, when the founder Phani missed a bus seat on a festive day and thought of starting first ever bus ticketing portal in the country.
 
All of these have been discovered purely by accident and the inventors have not started it as a process to discover any of these.
 
Answering 1st  and 3rd parts :
While there are innovations that happened by accident, NOT ALL the innovations in the world are the result of purely such accidents.
 
Also, would like to call out two words INVENTION and INNOVATION. An invention may at times come by accident and Innovation is difficult, as it is in most cases a combination of the invention, along with use, behavior, and business models, through a  rigorous process. A relevant example, i-phone that has been one of the greatest innovations in the technology. Inventions like touch screens, mobile communications for voice and data and many features of this gizmo were there for some time, but this innovation of i-phone is a result of a well-designed process making use of several inventions that were already made.
 
Ideation and groupthink are key components to innovation. Innovation is a journey.  Creating a corporate culture where the goals are measured in simplified KPIs and easily measured metrics might actually stifle innovation in many ways. Identification and improvements in these processes so that they fuel innovation can be achieved through Lean Six Sigma. 
 
Hence, I strongly feel a process is NOT AT ALL a roadblock in the effort towards creative design work and I see a tremendous value in the use of Lean Six Sigma in the world of product innovation.