Poe
For me, the Battlefield is difficult because you're not just fighting the RNG, you're fighting other players, and the space and resources are limited. In order for some to win, others must lose.
The Etelia event is difficult because the monsters you need to face on the Tundra are harder than any other you face elsewhere in the game. For those who consistently play the game and have built up an arsenal of strong pets, it's fairly easy. For those who are not as involved, are new, or have focused their attention elsewhere (e.g. people who exclusively breed deviants, collect custom skins, etc.), it is very hard to complete.
I definitely agree that there really shouldn't be two events at once.
Russaria
Luck varies a lot between users, as in any game. And there's nothing wrong with working together, provided everyone benefits, of course. But I think that 250 explores is excessive for finding only 2 pearls. Do you all have a high-level Astrologist? Are you using level 41+ pets? Are you uncovering the whole island and collecting every single shell you find? If so, it really could be just terrible luck. But I'm very certain that the drop rate itself hasn't changed. I can imagine no reason why it would.