I would generally be against this change. Others have noted that the change effectively prevents anyone from ever accepting a 0-confirmation transaction, which I think is a net negative for the bitcoin economy. I think this change will also make accepting 1-confirmation transactions (and to an extent, n-confirmation transactions) riskier. If a customer were to receive something of value after one confirmation, if the block that included the transaction is orphaned, and the new block does not include said transaction, the transaction is again unconfirmed and can be trivially double spent.