This is as simple as adjusting values if the system seems unbalanced once we've had a chance to try it. Increase/decrease the penalty for certain crimes. Increase/decrease max and min rep values. Increase/decrease how hard it is to grind rep (I've already heard it's easier now than they envision it being longterm).
If grinding max rep and then craping on said max rep is considered an easy abuse of a system then the problem isn't with the system but simply the numbers. That's a VERY simple fix.
The problem with this logic is that it's not addressing the root problem, that if something can be abused or used to "game" a mechanic, it will be. A reputation system addresses the core mechanic of belonging to specific factions, nations etc and hopefully ties neatly into many of the empire building, TC systems etc. that are planned. But you still need a system outside of this that addresses two things:
1) Actions that negatively impact another player's experience, needs to carry with it a significantly high penalty that is felt immediately. (Reputation systems would not allow for this as they are a slow burn - grind up rep, slippery slope lose rep)
2) We assume all factions treat random murder, hostile actions etc. the same. (outside of other established mechanics such as TC, Guild politics etc) no matter the reputation of the individual.
I'm not saying that the current iteration of the murder/rep system is good or doesn't need changing. That said, the two pronged approach of a murder/reputation combination does address the right problems - e.g. that there needs to be immediately felt consequences to someone's actions that impact on another player's experience (murder counts), but also that there needs to be consideration given over the long term as to which nation you wish to belong to (reputation) and reward a player for participating thoughtfully.
As such, I don't agree with this thread's suggestion that reputation alone is the silver bullet for the problem.
EDIT: I should add @Kaemik, I do think your reputation suggestions are good and does allow for greater control and impact on reputation based on the actions one takes against an individual, so I agree with the post on that note. I don't think limiting the amount of reputation loss from a single player capped at 100 every 5 minutes is necessary though (timers in multiplayer games should be avoided where possible due to the performance impact of tracking them across many players and in this case, each player to many players)
