it could be handled that way sure, but then we have the 'cries' of invulnrability mode etc... roberts proposal does not stop players taking 'damage' but mittigates the damage a player can do on another and also can be used to enforce a no PVP policy without radically altering the 'immersion' that for some removing all damage would do...
The main problem with points systems or crime & punishment systems is that whilst adding to the immersion, they also create potential loopholes and opportunities to abuse them and as such require constant fixes, rethinking, tuning and so on. And at the same time they won't be seen as a good solution by many PVE players.
People who play in private PVE groups or solo essentially made a choice of creating a cutthroat galaxy that is less cutthroat than Open. They effectively made their gameplay less immersive and realistic and so are willing to suspend their disbelief in order to play this way. I'm under impression that people who play in Mobius are not interested in any hostile / combat interactions with other players at all or only in a situation when both sides agreed to fight each other in order to make PVP rare and meaningful.
In general current crime and punishment system seems to be fairly realistic. For sure it is a bit too soft on criminals (player and NPC alike) who really should be becoming outlaws, with no option to dock in the systems of the faction they committed crimes against. I also think FD could strengthen the security in those systems that are supposed to be more secure and I'm happy with any reasonable changes to the system of bounties and tweaking it. But I don't see how they can make sure PVP is rare and meaningful without some form of built in invulnerability. And then again, it's not something they have to change in the current Open mode (issues here are a completely different kettle of fish) but it would be good if they allowed PVE players some more choice.
They have introduced CQC for the PVP players and that's a nice gesture towards this sort of gameplay. If it's PVP combat somebody wants, there is a place now where they can find opponents and have fun. This still didn't stop some players from going after an easy prey. Because there will always be players interested in disrupting game time for others by hitting some easy targets as opposed of looking for challenging PVP opponents in an immersive PVP context. They are not interested in PVP, they are interested in harassing other players. Presence of such a group of players in the universe is much more unrealistic and immersion breaking than an invulnerability mode to which participants agreed by playing in Open PVE.