We are not proposing any governance changes, as usual darknodes (who bond REN) are those with governance rights.
The core token utility would still be to bond a validator. If we introduce subnets, there are potentially more ways REN could be utilized, such as bonds for deploying a subnet to Ren, or used for paying transaction fees in subnets, but this is a completely open design-space which we invite more discussion to.
I’m not sure on your question, the general use of the term ‘validator’ entails them being block-producers as well. For the Ren core layer there is just the darknodes like before. Subnets might look different though, they are meant to be flexible in how they can be designed while being deployed to Ren.