1) The incentive for PKs in the low-level band is very, very small. Getting as much of a bonus as you can for it doesn't add up to even, say, Strong Back.

2) I think the game already has enough incentives to power towards hero. It's what most people do most of the time.

3) People always seem to want to extend newbie PK immunity or try to discourage low-level PK for love of the newbies; I don't think this is helpful. It just kicks the can down the road. If I had my druthers PK probably would still start at 10K XP.