I think most of us would welcome such a feature. But be aware that whilst it sounds like a boon for new explorers it could actually make things worse for them. If you make it easy to cherry pick undiscovered systems then that is inevitably what people will do. The end result is that those systems fairly close to colonised space that are now undiscovered would very soon be snapped up. So all you would do is increase the rate at which the bubble of fully discovered systems expands.
One of the devs also explained some time back that this feature would present technical issues. Right now, the things you can filter for on the galactic map are all held locally and only updated at best when the client software is updated (*). So if you just added the discovered aspect to this it would quickly be out of date for those systems ripe for cherry picking. The alternative of querying the server for them wouldn't be straightforward given how you can quickly scroll the map and potentially need to see the state for thousands of systems.
* - this might have been changed to allow for Powerplay, but that only involves a relatively small total number of systems.