This is a nice possible extension, but goes against the core spirit of ERC4337, which is full decentralization - each contract is expected to supply its own centralized url for authorization.
The idea itself is not bad - but it is not general.
Also, there are different type of transactions, which might use different authentications. Your model supports a single authentication per wallet.
We do believe that major number of wallets will try to be decentralized - that is, not rely on external service, maybe except for recovery
Also, there is no mention how the actual on-chain validation is done with relation to the "Authenticator’