cidFeeWallet in SubprotocolRegistry and CidNFT are currently immutable addresses. Allowing the fee recipient to be updated may be appropriate for future proofing such as to allow moving the fee recipient under DAO control, or similar change.
You could allow transferring to another address, potentially with a 2-step process. However this would increase gas costs as immutable could no longer be used.
An alternative which preserves the current gas efficiency, is to use a simple contract as the wallet which escrows funds that can be withdrawn by its owner, which potentially uses the OZ Ownable2Step mixin. The owner could be an EOA at first, and as the system matures it could be changed to a multisig or a DAO in the future.
