I'd like there to be  a way to auto validate and save the value of the satisfaction survey that the user clicked in the email (great,OK, bad) without having to click “Submit feedback”. The comment could be entered in a second time ...

The reasons for this:

1) The user might feel it is already submitted as he clicked on a result in the e-mail

2) The less click there are, the most answers we'll get

3) As the Web form is then pre-filled with the answer, the user might think it is already submitted, without even looking what is shown under, in the rest of the form

4) The user might think he MUST enter a comment to submit his evaluation, which would stop him in the process