Not important to your point but executing this attack using the coinbase transaction requires brute-forcing 40 more bits in the first stage, which makes it fairly impractical.
To add to this list:
- This is a roundabout way of closing the fake inclusion attack vector instead of addressing the root issue that 64 bytes transaction are indistinguishable from inner nodes.
- This requires miners to update their software stack, whereas making 64 bytes transactions invalid doesn’t require them to do anything (if they aren’t running a non-standard Bitcoin Core).
Even then for an application which checks the SPV proof of transactions for received payments this would never be an issue as they would only check transactions paying to a normal scriptpubkey in the first place, which would implicitly ensure the transaction is never 64 bytes.