a) we already have an openhab2 tag that can be used.
b) Adding a v2 “section” would not resolve the “Which version” question for the same reason that the openhab2 tag does not: People post questions in places they don’t belong. There is no technological fix for this.
I kind of agree with Max_G, if this was done months ago many problems related to the 2.x migration could’ve been easier to figure out since (at least I do) we search the forums a lot for solving problems.
If there was a separation of OH versions there could also be a subsection for bindings for each OH version as there is now. The exception (IMHO wrong posting is an exception, not the rule ) of people posting under wrong topics is always gonna be there but is also linked to how intuitively the forum is organised.
However, it seems now (I don’t have any data on this, just my observation) most people have migrated to 2.x and doing this change now would maybe be pointless…