Instances ruined EQ, I hated not having random people in zones that you help. The only *good* was in WoW with the dungeon generator so you could join with other random people.

Training and griefing? Not seen it yet but we have had a big influx laterly so maybe a problem at lower levels.

As much as I hate suggesting it, it would be a benefit to the game to reduce or remove xp for higher levels in lowbie dungeons. At the moment I can gain more xp in low dungeons mass slaughtering mobs which hampers lowbies getting xp