There will be a five-player maximum for groups in guild wars, so even though the game is trending more towards WoW in several respects, it is still keeping to a small-party scale for dungeons and high-level encounters.
Is this is a problem for those of you considering GW2? Does the game need to allow for 10+ players to make end-game content interesting or is 5 enough?
Personally, I'm fine with it, but I can imagine others thinking that it diminishes the game.