My thoughts on the whole Open, Solo, Private situation is that Open should carry bonuses to Cmdrs and factions if you complete missions, Powerplay and CG's etc using only open. As soon as you mode switch you lose said bonus. This way the people who run the higher risks get the better reward.
It's a nice idea, but ultimately runs on two assumptions I don't like. First, that higher risks give rewards because a game is defined by those stakes. Maybe twenty years back, but these days, a game is defined - more or less - by entertainment or pleasure. I know this wasn't your point, but it underscores the distinctions of what is most important, and from that the scaffolds emerge. Essentially you're looking at ways of protecting the Open scenario on the basis that difficulty should be rewarded, so the game needs to find a way to protect those who take on harder difficulty from those who could do the same tasks in a subjectively less difficult space. So the game becomes managed by an out-dated (but popularist) concept. It's not true.
Secondly, it promotes that idea that modes of play that are group orientated should be ring fenced to make their game-scape more "fair". What gets me about this is that game-scapes in Elite are entirely individual. Where your community is online, or offline (such as this forum could be considered), the game-world of Elite is singular. That is the constant here. We as players are just players. The different modes create different outcomes that we can prefer (if you like the challenge of human players, the risk, and the social: Open, if you like the structural challenges, isolation, and no-distractions: Solo - private groups sit inbetween). The constant isn't any of those states. None of them are the "way to play" and the others variations on a theme. This is important because if you accept this, the merging of these modes and their affects on the world of Elite matters far less. So whether people can flit between modes, or sit in what could be considered "easier" modes, all of which that might affect the goals or PP that you are immersed in (regardless of mode), makes no difference. It affects YOUR world, yes. It affects EVERY individual playing, and their world. You adjust to those changes if you need to. But ultimately you are just one person in a big messy complex industry of events.
Example, as I'm aware I'm being convoluted. 
Sort of like running a medium sized business, and the industry shifts around you. You can affect some decisions, with some other businesses you are affiliated with, you can make some larger changes, but you can't affect every decision and determine every change. And not every effect within that industry may be fair, or as you planned, or as you wanted. Some may affect that industry through powers that make their methods an easier play than your business. They may have large networks created by their dads, or money left to them from a large inheritance. As players, they may not sit on your playing field, and it might make their life easier, but you can't help that. That's how it is, and the world adjusts (unfairly sometimes) accordingly. In all this, the only constant is there is "an industry", just like we have "the Universe of Elite".
So this is like Elite. PVE, PVP etc, all play into the Elite Universe as if it was an industrial mess. It's not a level playing field. Some might exploit, some may play by easier rules (PVE), but ultimately, does it really matter? That's just like life. It's messy and you deal the cards you are dealt. Is that not really what Dangerous truly is about? Unfair odds?