It would only be logical to require a "vaccine-strain" that has the capability for uncontrolled spread to go through much more stringent trials and paperwork than one that is limited by distribution.
The whole argument about attenuated strains being a possible shortcut seems to be a variation of the "natural medicine" fallacy.
Except the experiment has been done for us already by nature. We are not doing the experiment, just observing what has already happened. Sure you would not be able to make a strain of unknown attenuation in the lab and spread it around (this would be very dangerous), but you can use the data that nature has provided us. I am proposing we go and collect that data.
The whole argument about attenuated strains being a possible shortcut seems to be a variation of the "natural medicine" fallacy.