Yes, there are other avenues to get EP's in this scenario. However, if someone finds themself in a range with easy/newb kills, this system can incentivize they sit there to hit each tier, so they don't have to do the explore part. Yes they are seperate, and you can get them without PK. But if certain players can exploit easy kills to reach those marks, they will. This obviously doesn't go for 90% of the PB, but those 10% will find a way to ruin it. I for one, miss PK EP, but understand why they are gone.