Pierre: Thanks for the answer. Then if you want to narrow down that area, product line specification and verification, then which specific issue/topic you would suggest to investigate?
Thank you all for the answers. Very good points. Personally, after some thoughts, I would like to mix Formal Specification with MDA or generally MDD. I mean, a Formal Model Driven approach. That is what I am thinking more to now and need a new narrow interesting idea as the area is too wide.
Perhaps it is better to ask this in a new reformed question.