Good list. My comments (please correct if wrong):
- Parsec requires 2/3rds of nodes to agree for consensus to be achieved. So for the entity with lots of nodes, I think they’d need 67% of the network, not 51%, to call all the shots. But I guess once the entity got over 33% they could throw a wrench into things by not letting others reach consensus. Maybe at that point they’d get the boot? Interesting to think about.
- An aspect of the Google attack that wasn’t mentioned (edit: actually you did have a sentence about it) is what happens if a big part of the network’s capacity suddenly disappears. There is a good thread on it here Analysing the google attack. The network dynamically adjusts the farming rate to try to keep a certain amount of spare capacity available, but at some point a big loss becomes too much to overcome. However, network restart capability can help bring things back up if this occurrence wasn’t malicious but rather due to disruption of internet communications for example.