You are not the one that needs to be convinced, that would be Sandro
I'm in favour of the game encouraging increased player interaction, both co-operative and adversarial, and I hope the new PP proposal succeeds.
The biggest factor is the number of players affected. Some will return or new players will come, attracted by the change. And of course some will leave or generally be nonplussed by having (what may be to them) an important motivation to play removed. From FDev's perspective this is probably a win/win, they either boost sales (revenue boost) or have existing game owners play less (lowering variable infrastructure overhead). We don't have the numbers for this so it's pretty pointless to argue the case either way, it can only ever be conjecture.
So if my challenge is to play devils advocate to the OP's test my approach will need to be to undermine the premise that more power players is better.
I have previously challenged the OP to change my mind that PvP players can't organise anything meaningful because of internal bickering (clearly a blatant generalisation), so I'll continue on this approach and expand it:
I believe a significant number of what I shall call genuine power players will be pleased by this change (if implemented) because they believe it will give them an advantage over the status quo. I think players in solo & groups act for and against all powers so status quo will probably be maintained (no benefit, Power Play is not improved).
In addition there are a number of what I shall call 'true PvPers' (players interested only in fighting for the fun of it) who believe they will be able to use this change to pew with impunity. However imo the 'meek' players are more likely to simply leave PP than move to Open, and those new PP players will be the rather more robust returning players or new players seeking a challenge - This should be good for the 'true PvPer' community overall (in terms of population) but there will be fewer easy targets than some seem to be expecting, instead of being able to farm PP traders they will themselves be either farmed or any influence they hope to gain will be cancelled out - again status quo will be maintained.
So I don't believe this change will be good for PP, but it should be good for Open, making it a less toxic place as the gankers are rendered too busy defending themselves to be effective against non-PP players.
So longer term Power Play will probably be no better off overall, but Open should become more palatable for those who currently avoid it as the PvP players will be too busy with each other to bother with the non-pledged.
As a final point MMO style gameplay does need some griefers to help keep the game exciting, but too many will kill the population quickly, so if the result of this PP change is not what I suggest above (ie it becomes griefer nirvana), the alternative is that the population playing in Open will nosedive, as of course will the by then Open only Power Play. Fortunately the game offers groups & solo so overall the game shouldn't suffer too much.
So the effects will either be to make Open a bit better, or a lot worse. Power Play will either broadly maintain it's population (as mentioned we don't have the figures to speculate reliably) or this will kill it off.
