I don't think off-blockchain is the answer. This completely undermines and defeats the purpose of the block chain being an open ledger. You might as well be another Paypal. The reasons invoked for off-block chain transactions are that the merchants’ volume is too high for the block chain, that the fees are too high or that confirmation time is too long. For every single of those problems there are known solutions that aren’t detrimental to the block chain ecosystem.