I can only speak for EU Datacenter and from what I read on the english forums about NA servers but in my opinion BA or rather open dungeons do not work in our society. It brings out the worst in people.

My experience (Iam alot in Eureka) is that Parties withing Hydatos NEVER form. No one shows interest into portals or BA. Sometimes they max get 1 Party together (which is really rare) shouting AFTER the boss is dead. So there is also the problem of being 0 prepared. So the solution for most people is: premade parties via partyfinder or via a discord channel.

Now, once those Parties manage to get into a instance together and people figured "wait, there are 4 parties int here who wanna do BA" THEN all of a sudden everyone has interest and its "everyones portal" so the result of that is, you guessed it, sniping. If to many sniper make it into the dungeon the result is the premade group leaves and everyone just wasted their time. Or if a sniper gets invited into the group it usualy ends up the sniper wiping the party. Another waste of time on everyones hand.

On EU Datacenter we even have a whole subculture of people lurking in Discord Channels and stalking premade groups, instance hoping with them, "stealing" a portal and mocking the parties who entered. (and yes those people get reported for stalking)

(please note Iam not saying everyone who uses a portal without a group is a sniper or does it on purpose, but lets be honest, most people do it "just to prove a point" or to get some sort of kick out of it, aka trolling)

We as a community failed. For some reason we do not manage to play together and respect each other.

My opinion is if you do NOT manage to get a bunch of people together inside eureka with a serious number of people to actually can encounter bosses (before the fate spawns, you rly need time to prepare) please let people with premade parties enjoy the content.