I really hope Blizzard can remove the Meeting Stones and the Warlock Summon spell. And here's my reasons for that:
-It fixes laziness: People who really want to do the raid or instance, have to get there themselves. As soon as you are invited, you should start making your way there, and not lurk in a city, where you most likely saw the guy spamming trade for that ICC raid...
-Symbolizes the return of hardcore: Blizzard have hinted towards are more hardcore friendly game in the entire beta. The boss encounters are harder, more sophisticated mechanics and it takes longer to complete the dungeon. Why not remove any carebear way of getting there? It seems like a false safety if you can get there with no effort and then get hammered by the encounters.
-Sufficient Lore reasons: Deathwing's return shattered the ley lines of the summoning stones to a point of no use. Warlocks can not create the Summoning Stones as well because they operated on the same ley lines.
-Exploration: If you have to fly to the encounter, you get to see more of the world. And while you fly, you can alt-tab and look up some strategies on the encounter.