So there is this now dead game called next day survival, which tried to take on a stalker vibe and put it into an open world online game with quests and what not. I think that I would personally enjoy Fear the wolves much more if it had something like that, and the battle royale was something that you did within that game, kind of like its own mission with a good reward for winning, but maybe you risk losing a character or whatever.
Anyways, I just thought I'd share that I thought it would be cool to have a kind of open world stalker game, and I'd also like to point out that Next day survival kind of died when they added a battle royale mode (though in my opinion it did not look as good as fear the wolves)
It should go without saying that as a fan of stalker I can already appreciate this game for what it is currently, and I look forward to playing it.
In short, add a DayZ style / Free roam and keep the anomalies switching around the square grid, but don't have it close up to a choke point, and I think you will attract that audience