When I heard about Flex Raiding or Flex large group content (however you want to call it) I thought that it sounded like the best modern idea for endgame group content in a while.
For those that don't know, Flex Raiding (as it will be implemented in the new WoW Expansion) means that a Raid (normal or Heroic mode) can have anywhere from 10 to 25 players and will scale in difficulty accordingly. For the extreme hardcoe, a new mode will exist specifically calibrated for 20 people (I think its called Mythic or something), but other than that, you can have anywhere from 10 to 25 people for large group PvE.
This is awesome. You no longer have to force guildmates not to Raid with the Guild, everyone can just join - no one needs to be left out. You also wont need to spend hours looking for similarly experienced people if some players don't happen to show up (especially if you are missing the tanks and healers). You will never have to cancel the Raid because enough people did not show up to fill 24 slots.
I think Flex Raiding is probably one of the most brilliant ideas for modern endgame. It removes essentially most of the drama and toxicity that we have come to know and love about Raiding. From what I understand, Heroic Raids will still be ridiculously hard, so you are not sacrificing quality for accessibility. And if you want to do the ultimate hardcoe content you are still free to organize a 20 man raid, without hurting the more casual gamers.
I would LOVE to see a similar Flex Large-Group-Content system in ESO. As someone who has done hardcoe to semi-hardcome Raiding for almost the past decade, this sounds like one of the best ideas I have ever heard. I see no downside to this whatsoever, and at this point, I think any game that does not have a similar feature would look obsolete.