I think we should handle it as we have done so far. We have tags for all sort of not even close to SharePoint coding, such as jquery or the tag java-api. Instead of disqualifying questions based on coding language we should look at it the other way around. If you try to do anything with SharePoint, in any existing or future programming language, it is a valid question.
A SharePoint DEV stack tag would be too wide. It is valid for any of our coding question and doesn’t make the question clearer.
When we discuss Frodo and his quest to carry the one ring to rule them all into Mordor, I think it’s a bad idea. Maybe if the Documentation beta on Stack Overflow is a hit the documentation may spread to other Stack Exchange sites such as ours. As of now SharePoint is one of the documentation topics...
If SP.SE is valid when MS has published its new network? So far we are working alongside social TechNet, and both have its place and time. The Office Network, currently in preview, is more a discussion type forum or Blog comment forum to be any real competition. Here we are still very rigid about Question and Answer. Nothing else. This is our USP which hasn't been copied yet.