Why did our group of 1 tank, 1 healer, 1 melee dps, 1 ranged dps take on another healer? Because they weren't a rando, we knew they were a good player, and because we enjoyed playing with them.
Steven describes dynamic encounters as adjusting to the performance of the group. Certainly a group leader can decide that the goal is to defeat a boss in under 30 seconds, and if that isn't happening they can start asking questions and scrutinizing their group, but I frankly hope this is only going to occur for certain types of players and groups and not ALL of them. I hope the game will encourage groups to form and learn, and not sit in chat all day seeking to assess all players by a single metric - DPS.
I imagine a group running into a sort of dungeon lobby where players of various levels and classes are farming solo. As Steven has said, the deeper you go the more difficult the mobs become, so you can imagine a group of lvl 30s running down 3 levels and looking around for anyone soloing and asking if they want to join.
Once they join, the group can stay on level 3 and go down the hallway to fight groups of mobs, or can venture further downstairs to level 4. If this group is doing OK, they're unlikely to ask each other what their DPS is, because the success comes from the team and how it performs overall. There could be a person who does 3/4 the DPS of someone else, but they are a good group member, paying attention, and working together. In this scenario I could see fights taking a little longer, but the group isn't dying and is therefore satisfied.
Now if that same group leader wants to try to go downstairs to level 5 to get better loot, they may start asking their level 30s and 40s group members to own up to their DPS so they as a group can decide whether they have a chance to risk going deeper for some better rewards. But what I would hate to see is such a simplistic gameplay loop where burning down HP is the only thing that matters, so DPS numbers of group mates is the only thing that matters, so people sit in chat for an hour saying "LFM DPS 3k minimum" instead of just grouping up and playing the game. Remember, we want people to play the game, both casuals and hard-core people alike.
https://youtu.be/Jmgz9S__MOY?t=181
Certainly at a later stage of the game, you will probably not even go to particular dungeons until you have your group, and you're free to try to distinguish the best composition to bring in any way you see fit. In my DAOC days we might test you by watching you solo a certain mob to see how you handle yourself, but it would never be this disgusting practice in WoW where we watch you hit a practice dummy just to see if your gear and memorized button rotation = 3k DPS.
I'm hoping for a game that values the group dynamic, creative problem solving, and diverse gameplay styles. Not only is it more fun for me to just walk into a dungeon and be accepted into a group based only on my level and role (which still doesn't really reveal much about me and doesn't let you assume what I am capable of), but I think the entire game would get reduced to a lobby game like WoW if players are made to feel like there is only one good composition of a group and only one good way to measure contribution to the group, so they don't even TRY to form up and play the game - they wait for the perfect situation to make sure there are no surprises, no thinking required, and no risk. It also breeds more players who just pick the easiest one button build so they can mindlessly DPS, and I don't want to play with those people either.
I'm certainly not saying you should run into a dungeon with 4 bards and a ret paladin - you should figure out how you're going to be prepared for any challenge and have the roles in the trinity filled out - but you shouldn't demand tank, 3 dps, 1 healer all the time either. I've had some amazing group experiences with 2 healers that would have never happened if we hadn't played as a group, learned our strengths, and then selected challenges that aligned with those strengths.
Why did our group of 1 tank, 1 healer, 1 melee dps, 1 ranged dps take on another healer? Because they weren't a rando, we knew they were a good player, and because we enjoyed playing with them. Sure, adding another rogue or buffbot would have been fine, but if given the choice between the "meta" and playing with someone I like playing with and who is a reliable player who can think on their feet, I want the game to allow me the freedom to pick that person and still find a way to succeed, and not be forced into picking the rando rogue with an attitude who doesn't talk and ninja loots the 2h.
