Again, you are comparing 'what is', versus what is proposed, and as far as what is proposed, given it is a completely opaque system you will need to trust CR (good luck with that) and also between now and then prepare yourself for various course changes as we have already seen time and again, course changes generally driven by commercial gain and pandering to the mainstream, many more of whom prefer pve to pvp in this category of games. To test this hypothesis just go take a look at how very few pure play PVP mmos are out there as compared to 'consensual only PvP mmos', a term I hate because it implies pvp without opting in is analogous to a sex crime.
In either case lets look at what is proposed. For all those SC fans talking about the potential 'abuse' of using ED solo mode to build 'advantage', please tell me in the proposed system for the SC PU, What stops me putting the slider up and down at will from one mission to the next? Answer - nothing. Therefore if you are right about this fear, get ready for it to be abused even more in SC land, in fact I can envisage the pvp slider becoming just another variable setting like difficulty with people recommending doing such and such mission on pvp slider setting 'x' and another mission on setting 'y', while best to travel to such and such system on setting 'z', etc etc.
This is one of the many reasons why, if there must be a compromise, a universe in which you are transparently either in or out, with no grays in between, is far superior to this ridiculous slider concept, and the height of immersion breaking gameyness and side stepping the issue that it represents.
I imagine the PvP slider being bound to an axis on the joystick.