The other attacks you describe all derive from the fundamental reason I declared all non-proof-of-work systems to be insecure back in April.

My logic was mathematically fundamental. The input entropy set is quite deterministic and well known and thus can be preimaged. For example, accumulating a lot of coin-days-destroyed and then targeting them in clever ways to subvert the security.

The randomness (entropy) of each proof-of-work is fundamental and mathematical and it can not be preimaged. It can only be surely defeated with > 50% of the network hash rate.