What is the purpose of having multiple of the wallet offline and selecting one for transaction vs having multiple offline wallet?
I mean before you can make transaction, you have to connect the wallet online which does not make it a cold wallet anymore. So any used one will be considered not as cold storage anymore.
Altcoins developers are lazy to develop wallets like Electrum. Worst thing about them is that they prefer the wallet to remain using just one address. Instead of having lists if addresses.