The issue is not the rebuy... rebuy is onerous enough already for law abiding players. The issue is that there is still too much crime and not enough punishment.
Where players attack and destroy other players' ships, as well as engaging in illegal destruction of NPC's ships, the penalties need to be much more severe. Bounties on murderers need to be much higher than those for pirates who use non-lethal methods of stealing cargoes.
Additionally, those players guilty of multiple murders should have bounties so high that both players and NPCs alike will be swarming to claim the bounty, any system which is not Anarchy should eventually become off-limits, with all stations firing on the offender automatically - thus forcing them to the lawless fringes of society, and finally, any player killed who has multiple murders on their file should have their ship confiscated and destroyed for being the tool/proceeds of crime, with no rebuy, and they should be imprisoned at a penal establishment in a sidey with no weapons or frame shift drive and no access to any remaining funds or ships until they have earned their way out of prison, by carrying out penal station missions... doing meaningless, tedious tasks like scanning 20 incoming or outgoing ships, and then paying their way out of jail with their prison-earned funds.
... possibly all the while with their presence being advertised to the galaxy for anyone who has been wronged by them to come and try to kill them in their weaponless prison sidey.
This would make the punishment for antisocial behavior quite real... if the punishment missions paid out much more if conducted in Open, and any CMDR killed by the prisoner told where he is imprisoned so they can come and take a free, authorised shot at him, there would be incentive to do the prison grind where those wronged by the prisoner could come and show them the error of their ways.
The prison missions could be set up to require perhaps 8 hours of grind in Open, or 40 hours of grind in solo, so the criminal couldn't just wait out his imprisonment. The prisoner would also have to cover rebuys on the prison sidey at an increased percentage if killed by wronged CMDRs. Give them a taste of their own medicine...