That's not necessary. A transaction with a modified id is not a problem unless you falsely rely on the id for payment verification instead of tracking the input

That's not necessary. A transaction with a modified id is not a problem unless you falsely rely on the id for payment verification instead of tracking the inputs and outputs by a custom hash. The biggest flaw here is probably the name "transaction id", because it suggests that a transaction can only have one valid id. The normalized id fixes this issue for most transaction types.