I've often caught myself thinking this as well, but a larger party size is not a good idea imo. First off I believe it makes it too easy to shit on another, smaller team this way, but I also think that the strength of "party buffs" is a bit too much at the moment. Because of this, I believe the best solution is to reduce the party size to 5 or 6, and then add in a raid system that can hold up to 20-40 people.
Players in the raid would not get hit with abilities / leftclicks from fellow raid members, but the groups themselves would be completely separate entities. This, by the way, is a standard for all MMOs. Whether it be PvE or PvP, groups are kept small, raids are kept large, and everything is done on a per-group basis.
This means that group buffs/heals only apply to portion of the raid (the group that they are a member of). Sure, you can heal fellow raid members, but you cannot AoE heal them, and if you wish to buff them, you'd have to either target them directly, or join their group to receive the benefits.
This would allow more players to "play" with the team, but would also reduce the benefits of things such as chakra, groupheal, and might/warsong. This would be more fun, and it would also be more balanced.
If we modify parties in any way, I think
this is how we should do it.
Kainzo , thoughts?