Please implement a notoriety/flagging system in the style of Ultima Onlines current system, compare
http://www.uoguide.com/Innocent
http://www.uoguide.com/Gray
http://www.uoguide.com/Murderer
in Order to have the server keep track of who plays as a notorious murderer. This would also enable a gameplay that actually makes sense (like being able to kill those who heal a murderer without becoming a murderer oneself). The color flags of the names could be visbible through "checking pulse", however I think the flag should also be visible when directly looking at a player. Even if the flags are not visible ingame at all (and are not even reflected in characters hair loss or whatever) a server admin could, for example, set a respawn penalty according to the murder counts. If he wants to balance the amount of senseless killing, currently he has no way of doing so, which I consider suboptimal.
The basic idea is as follows: notorious murderes are flagged red and possibly visible to others as dangerous. Optionally they suffer penalties, for example a longer respawn time and/or slightly lower regeneration or whatever. If someone heals a red, he becomes grey and can be robbed and/or killed without the killer receiving a count or becoming grey oneself. Additional, server-specific rules for private shards could be set (for example, increased respawn time as an option, or other modifications in order to balance the amount of notorious murderes). Players could be more aware when dealing with players that are grey and potentially be more helpfull to those who are blue.
As the concrete ruleset on how to change the flags should carefully be adapted to DayZ, I think this should be introduced while still in alpha stage.