If you were to take old transactions and roll them over to new genesis transactions at the same address but without a need to validate a history, I think you could safely drop the history of those coins without any affect to the end users. Probably would need to have the new genesis transactions on the chain for a few hundred or thousand blocks before the history was dropped to prevent malicious actors from forcing history to be dropped early.
@silverpill @monero @tusker
If you were to take old transactions and roll them over to new genesis transactions at the same address but without a need to validate a history, I think you could safely drop the history of those coins without any affect to the end users. Probably would need to have the new genesis transactions on the chain for a few hundred or thousand blocks before the history was dropped to prevent malicious actors from forcing history to be dropped early.