Correct me if I am wrong but this should also have a rule that if you CALL the storage address, this should not get removed from the state. I am pretty sure that accounts which have non-empty storage, but no code, nonce 0 and balance 0 are DEAD and should therefore get removed from the MPT (thus clearing the storage). The alternative could be to just send 1 wei to this address, but it should be noted in the EIP anyways.