I’m a little late to the discussion, but firstly I agree with shifting ROS 2 questions over to ROS Answers. I think there is a large enough mass of users now to make it worth beginning the build-up of problem solving information.
I also agree with having tags that are required to allow easy separation of ROS 1 and ROS 2 questions.
I’m not sure I agree completely with having distro-specific tags rather than just “ros” and “ros2”. I think that many questions will be appropriate for multiple distros, and while it makes it easier to see what was in use when a question was asked, it could potentially make searching more difficult. Something relevant to Lunar may have been tagged with “Kinetic” and so get instantly ignored by the searcher, leading to duplicate questions. The flip side of that is that the new question could be answered with “this is the same as in Kinetic, see this answer over here”, which provides not just a solution to the problem but also additional information that the same solution works in multiple distros. So I think it’s really a case of both options having pluses and minuses and we probably need to try it to see how well it works. Can we add “ros1” (note the “1” to make it clear) and “ros2” to the list of available required tags and see how often they get used after a few months?