Yep, I’m probably one of those fans. Though I also very much like the team-play aspect that usually comes with (instanced) group content. What I would like are random encounters you’d find in open world (possibly instanced) which would require people to spontaneously group up as a team of max. 5 to beat it.

Similar to Dungeoneering in RuneScape, but with occurances/entrances randomly spread out over the open world, using your current gear scaled to the level of the encounter and difficulty/rewards scaled to the number of people in the group.