As we know, Atlas has the Atlas square for community events, Praetoria has a very large vacant empty parking lot for community events if there are ever enough gold players, but Mercy has a very cluttered starting area. Tiny, sure, filled with atmospheric NPCs, very, but are they too much for such a tiny space? Yes.
I don't know what determines when/what triggered the civilians, but we can do less of those. Civilians and Longbows with their hands up? Maybe move them further back? Hedge and tall pointy trees that divide the centre area into small pieces - cut them down.
Attached is a dark hard-to-see screenshot of unnecessary clutters I mentioned above.