Narrations always make a good game, in my opinion. The Final Fantasy: Advent Children Trilogy () is a great example of this. The second game was one of the best I've ever been in, and I was only a villager.

Items I think are good, but depends on how they are used - could be game-breaking, but OTOH could make what seems a boring role a good one.

Super Smash Bros. Melee was good fun, because everyone had a role, though some appeared to work better at the start, and some better in the endgame. Lots of different roles can work, but the abilities need to be really thought through.

Role-playing can be good, but it depends on whether a) the person playing knows the content that the game is based on, and b) whether the player finds it easy to role-play in that context. I know there are plenty of games I have fun in, but can't role-play in, such as FF:AC. Those games are great fun, but I don't know anything about Final Fantasy - I watched the films, but payed very little attention to the storyline. But it can be quite fun watching others role-play, like Helgraf, Cristo, Shadowcaller, Griever or 'Goof. But again, that's down to personal preference...