Hi Grrizz,
The node blocking goes a little further than just that, because the change can be introduced ahead of schedule; it will help to make certain that nodes are already well-connected to (good) peers and that the network goes into the event without there being a disruption for DoS leading to islands of nodes that would otherwise take a while to settle if the node happened to have had all of its previous outgoing connections to *soon to be bad* (incompatible) nodes.
The contention in the PR is about how the node blocking is otherwise making "currently compatible" nodes, non-viable and is seen as adversarial; yet since doing so implies protecting the network when the other side does their "Network Upgrade" it is also seen as quite conservative.
All these things have to be done carefully; and I wouldn't want to be the one pushing code to so many users unless I was damn sure of the behaviors and emergence.
It looks like the Core devs are well aware of the system emergence the node blocking will produce (as designed).
I would rather see the swarm aligned for network segmentation ahead of time, then play a game of entropy roulette looking for peers when all of the good nodes have already reached their maximum connection limit.
Best Regards,
-Chicago