The threat is that the unfairness rises with pool size, encouraging the largest pool to become even larger. Once a pool becomes very large (e.g. over 50% of the hash rate) it can DoS the entire Bitcoin system or use the threat of DoS as a form of blackmail to make changes to the protocol.
even if you've got future blocks precomputed for weeks in advance, all it takes is someone else finding the current block by chance to completely invalidate your private chain?
No, because peers use the longest valid chain (more or less) regardless of when it is revealed.
even if you've got future blocks precomputed for weeks in advance, all it takes is someone else finding the current block by chance to completely invalidate your private chain?
No, because peers use the longest valid chain (more or less) regardless of when it is revealed.