These are compelling arguments, though for hardware wallets in particular, it’s a nice to have that seems to have been tacked on as an added bonus.
As for the original motivation of making on-chain behaviour more predictable, “…but the only way to achieve this would be to have a deployment sequence for all contracts you…
It’s actually more like a honeypot for people like yourself trying to withdraw the funds. The idea is this:
IMO, the term “Malicious Backdoor” is an unclear description and sensationalizes the issue.
This vulnerability lets an attacker conceal malicious code that can be very difficult to spot without a deep understanding of how Solidity and the Proxy Pattern work.