2 days! That's fast response
If you're not open in the design/pre-release phase you're likely to miss use cases and if the members have committed themselves to solutions and switched their focus to other tasks I imagine that there will be an unwillingness to go back and redo things even if new important insights have been revealed.
I think most users would like a code base they can build upon, not one that needs adaptations to make it work. Being fully transparent about the code in the making will reduce the risk for such adaptations
What I'm suggesting is free and efficient access to the collective intelligence of the entire community at a point in the development cycles where it makes the most difference. I'm not suggesting a shift in the rights to make the final decisions. That's exclusive to the paying members. What's preventing this from happening within Accellera?