It's also not one free of unexpected negative consequences in the case where the new system doesn't have a low value. Consider, a number of altcoins with more centralized administration have frequently hardforked and the ticker symbol and most of the value went to the new system while the old system was largely devalued.
So your policy would end up constantly resetting the holding period for these assets and the tax treatment would also be disadvantaged because it would tend to create short term gains and long term losses essentially out of nowhere.
E.g. You own Ethereum for two years. Then Eth hardforks to undo the execution of the DAO smart contract and return the lost funds eth's administrators. The original Ethereum continues, but the value and ticker symbol follow the new blockchain. A month later you sell all your coins. Did you just create a short term gain of the full value of the coins and a long term loss?
The hard fork was ethereum's failure as a result of the technical inability to roll back the transactions the proper way (i.e., by just undoing the redactions themselves) and the tax law shouldn't be changed just for that.
It appears to be saying in situation 1 you have no N-coins at all. By exclusion, situation 2 would apply if you have the new coins and it clearly states taxes are owned on the market value in that case.
IMO, the most reasonable interpretation without a specific basis-splitting rule, given that the IRS divides a hard fork into a legacy ledger a and a new ledger would be that the basis value for the new ledger entries (being that they are created by the fork at no cost) is zero, with the legacy ledger entries retaining their original basis value.