In City of Heroes, groups are where it is at. Pick-up groups are not hard to find, and they are rarely apocalyptically bad (although some are pretty weak). If you are in a supergroup or on a global channel, you know some people to group with. With sidekicks and exemplars, and auto-exemplaring in TFs, finding people “your level” is trivial. The game is not built around fighting one thing at a time, and there are many powers that do not hit their stride until you have a team of 4+. We love fighting huge spawns, and with the xp curve changes, fighting bosses (group size 7-8) is where the great xp is. All missions are shared instances, so everyone can join in anything. It is typical to keep a group going for several hours, shuttling in people as a few drop out. This starts as early as level 2, when people form sewers groups, and continues through level 50. Team composition does not matter: this is no holy trinity, and I have done a task force with 3 Scrappers and a Defender.
In The Lord of the Rings Online™: Shadows of Angmar™ PvE, grouping is not encouraged. There are several reasons why you might want to, from fellowship maneuvers to shared experience, but the quest-based leveling system pushes you away from sticking with the same people. If you are with the same people for more than a half-hour, and not in an instance, you are probably grinding enemies for a trait. When you reach a new town, you get a stack of solo quests scattered around the zone, some of which will lead to group content. You group for one quest, then Legohlaz has a full pack, Legolass wants to do her spider quest, Lejolas is working on a quest in the other direction, and the group splits. Repeat at next group content, except in the quest chains, where you split after completing the chain. Groups cap at six, so a couple of people leaving means you are paralyzed until you find new members.
I have yet to fiddle with The Lord of the Rings Online™: Shadows of Angmar™ endgame PvE content. There seems to be a lot of it, and it is all group content. I hope the expansion does not consign it all to the dustbin, since I am not going to be able to get a raid together for something 10 levels below the cap.
In The Lord of the Rings Online™: Shadows of Angmar™ PvMP, open raids are great. There is almost always one open, maybe two, and we get so used to it that we forget to start a second when the first fills up. Voice chat is lively. People are work pretty well as a team, even with random composition. You regularly see raid-and-a-half versus raid-and-a-half, with a player troll and a bunch of NPCs in the mix (no problems with my graphics card), so the Ettenmoors really does re-create that “war” feeling that so many games miss, complete with monsters that keep dying and coming in waves while the free people play conservatively and have far better kill-death ratios. It is the most fun I have ever had in PvP.
City of Heroes PvP feels lonely. There is so much mobility that the fight sprawls over city blocks, in 3-D up to the flight ceiling. The goal is to pounce on one squishy, crush him, then spring away before his teammates can react. The only alternative to skirmishing is the long, drawn-out brawl from They Live, featuring Tankers and Scrappers who take forever to kill with ridiculous defenses. The skirmishers may actually continue their bouncing bloodsport over the tanks who have nothing else to do but engage their similarly invulnerable counterparts.