Regarding healers acting as DPS

[AzureFlare]

Everybody heals differently. Everybody tanks differently. Honestly, if as a player you need to worry about satisfying the expectations of another player, without that player even mentioning them, while you're still fulfilling the expectations set by the game, then SE might as well put a giant banner when starting the game saying 'You must be a psychology major to play this game'.

The correct way of doing an encounter is ensuring the party doesn't fall while the enemy does. That's as basic as it gets. Even if you all hit the floor right at the end.