In my opinion, most of the problems never surfaced due to several posts from the Snapshot era, prior to Go-Live of KNXv2 (one example: KNX1 to KNX2 Migration Steps).
It is (critically) important to have some tutorials/guides/docs/migration scenarios developed prior to Go-Live of a 2.x binding that replaces a 1.x legacy one (your arguments in your first bullet of the OP).
As the time passes, the forum will develop more of that, so the problems will be easier to handle (users will be able to find more info and solve the issues by themselves).