There's also the idea of a snapshot and/or fork. The new vault could be on a brand new blockchain but use the same private keys or have a distribution so all existing balances are present on the new blockchain, so all people would have to do is import their old vault private keys and they have their coins.
The snapshot approach with re-using same private keys was exactly what we intended to do with CBXi. Still seen as a 50 000.$ "swap" by Cryptopia.
If you do a "fork", then you still use the old blockchain, but new vault software, and of course there will be two blockchains after that particular block, the question is if Cryptopia would accept the fork and replace the old coin with the new coin, or have some sort of "in place" swap that instantly happens on the forking block.
A "fork" is pretty much a common occurence in the altcoin world and it's not considered a swap by Cryptopia, this is confirmed by one of their admins.
All this being said, we are negociating with people from another crypto who want to create a new exchange, which would be CBX (and said coin) centered. Stay tuned.
Did everybody miss this? I think it's a pretty major idea.