Oh I'm not saying it will stop demands, that will never happen. I'm just saying we will probably get a counter to those claims. Lets say they implement this in Q4, won't be long before the novelty wears of and PvPers find themselves needing to PvE, since that's what Powerplay still is in it's core. You see people post how Open only will make Powerplay one big meaningful fragfest, but they are indeed as you say not taking into account the size of the playing area and the number of players in it.
After the euphoria, the reality sets in. And perhaps they will indeed focus on the BGS or demand mechanics designed for PvP (which is the way Frontier should have gone in my opinion, but it seems they're taking the easy cop out route). If this experiment fails, we'll have a precedent. I wish an interesting future for Frontier in this regard.
What does worry me is, if this is the way Frontier improves core mechanics, I am not very hopeful in the exploration updates.