The general argument about solo / open etc will always have detractors, but this is the way the game was designed from the beginning and I agree with those people making that point. All of the design decisions need to take into account that mode switching is allowed, and therefore any player to player interaction is voluntary. All other design decisions should be contingent upon that.
That said, I'm not sure whether I'm totally opposed to the idea of having time limits on switching from open to solo - i.e. if you're in open, you can't switch to solo until a 10 minute cool down timer has elapsed. I don't necessarily see this as a terrible crime against humanity, but I'm also not sure whether it would solve any of the issues being discussed.
I do not think that mode switching should be banned, contstrained to one commander, or whatever as some have suggested.
I also don't think the galaxies should be, or will be, split. It's been very clear that FD want one overarching narrative for the galaxy which is consistent across all modes and platforms. Again, this is a key tower of the game design and all other design must take this into account.
Now, regarding the community goals specifically, I hope that no sledgehammer is needed here.
1. The way Community goals are set and measured can be tweaked, and if necessary separate leaderboard could be maintained by platform and mode, but without impacting on the overall ability of the individual to play the game. If the control of a whole system or some other major story arc is at stake, on balance, I'm still not convinced that this should extend as far as the scoring system being weighted in favour of those in open play. I think that should be a last resort if it can't be solved any other way, and it can be proved that the situation is leading to the majority of players playing in solo during CG. My guess is that for a lot of players the fun is in the taking part and the individual battles, rather than the final result.
2. The way that NPC characters spawn can also be looked at, and the design intent should be clear around whether a wing of 4 players in a conflict zone should expect to get 4 times as many NPC targets per hour as a single player alone. If so, the average number of targets per player could be the same, so there would be no advantage.
3. As others have pointed out, player blockades were specifically designed to be impossible to enforce fully. Any blockade will be consensual on both sides, so that any player running the blockade in open is actively deciding to participate in that role play. Unfortunately if you don't like that, there are other games where player blockades can be enforced much more effectively. I'm not sure this point is relevant to the recent Lugh CG as I understood that it was based solely on combat bounties in the combat zone, but this could be relevant for other CG.
4. Other objections like "it takes me a long time to coordinate and form up my wing of players so I should be compensated for that" are, in my view, not really valid as an argument to give additional rewards.
In any case, I suspect that those who want to force a situation where CG are decided primarily by PVP type interaction are going to end up disappointed.