You actually can use the eRecovery to do full partition backup and restores, but it does not fulfil the user-friendly criteria, as it also needs adb and knowledge about which partitions to backup. It’s not space efficient and too only works to/from the same device:
Maybe integrating those adb steps into the easy-installer would be a viable user-friendly option, as installing and setting up adb blocks users. But as I said - it’s not space efficient.
It really is easier to wait for Seedvault to come to fruition. You can give it an early peak in here.