The IMMs have implemented so many changes that stifle the ability and the desire to PK, it surprises me that they actually want to see more of it. These days, there's so much build/class/race specific gear, that unless you're a shifter PKing other shifters or something similar, you usually cannot use most of your opponents things anyway.
Some changes that reduce PK in some way:
-Forced hometown diversity
-No PK edgepoints
-Removing third hand light sources
-Race specific gear
-Class specific gear
-Anti-gank code
-Bard gank nerf
They are not all bad changes, but definitely have an effect on will/need to PK.