To argue that OOPP would not shut out those who don't enjoy PvP is disingenuous at best. OOPP would force players who wanted to affect the feature to play in Open - where any other player could choose to shoot at them if they instanced together, for any or no reason.
Detail is lacking in the claimed "feasible ways to cater to both" in terms of accommodating players with no interest or desire to engage in PvP in Open-only anything in a manner that those players would enjoy..
That said, when Colonisation is released, one possible way forward (on the assumption that it would be possible, of course) that I would hope that Frontier would consider would be to create a permit locked bubble of currently unpopulated systems (the exact number does not particularly matter as there are billions, however too many would likely dilute the desired outcome) near the existing bubble and only permit players who select are playing in Open to access them.
Such a volume would effectively create an Open-only area in the galaxy for players to colonise, which could go some way to providing a solution to the gameplay aspirations of those seeking Open only <insert feature(s) here>, without taking any game feature away from players with no interest in PvP. This assumes that Factions will be a part of colonisation and that Powers will be able to expand in to colonised systems.
You're right, I misrepresented the situation in that comment. I had lost the plot.
While you're right that I have been (unintentionally) disingenuous about OOPP not shutting out PVE'ers I also think it unjust to say that the current version accomodates to both PVP and PVE equally. I do in general think that participation in PP as it stands now ought to be solely PVP enabled. But I would be okay with the current state of PP 2 if there were ways in which you could hinder the solo players through PVE means. NPC ships and modifiers are what I intended to be a few examples of this.
We don't really have that now though, and wont have for the foreseeable future. In the meanwhile we have a system that makes PvP superficial and inefficient; effectively shutting out those who do like PvP due to it's inviability through people still being able to reinforce/undermine/acquire in solo. There seems to be no real point to PvP as both parties would be better off affecting the systems in solo, without resistance. Which gameplay wise, at this current moment, amounts to a race to get the most rare goods/merits as fast as you can, without having to worry about resistance. Literally just Feds and Imps trading alongsides eachother, albeit invisibly, trying to be the first, which is not really what I imagine the designers had in mind for PP.
Perhaps frontier ought to completely separate the two like you suggest above; or we find a compromise for both in some way. And I don't think this system is the compromise that we need, given that I feel PvP players are being shut out from meaningful and viable interaction with the system, like shooting themselves in the foot. As you said gaining merits is a form of viability but the main purpose in combat would be to hamper, not to gain. That's how I see it anyway.
Perhaps I was focusing too much on open and solo play while my main gripe is there is no way to push back against those who play in solo. If not instanced PvP, why not NPC based war coordination or what have you. OOPP would be an immediate fix imo, but this could be another solution as could be your secondary bubble. You could say go to solo yourself and just do the same, yes. But that would water down the playstyles a lot by creating an isolated and monotone experience, no?