If you put a legendary drop on all GM2/3 Stronghold bosses I think that would fix the issue of people dropping at the boss fights. Another good idea is to place on the bigger Titans in Freeplay(assuming you revert them back to their former glory).
all they have to do to stop people leaving mid mission is make the boss drop EVERYTHING except what drops off the mobs themselves. so no chests at all in level.
it really doesn't matter at all at this point. you can tell by how slowly the replies on this forum are rolling in that the majority has already walked away from the game. they should have released it a full month early on pc (with an extra week for premier) and that way they could have RAPIDLY deployed patches to fix the countless issues every other day rather than having to stack up huge patches to float by sony approval process at a snails pace for the sake of keeping all platforms on the same page (the next patch we get is already in the approval phase, which means they aren't even working on anything that will break because of it, they are working on the patch after that). kind of sad really.. but ultimately I dont know why we expected anything but disappointment from bioware or ea after andromeda.