It didn’t have a purpose, and actually many people speak out against clans.
Clans went down in H2 due to some stuff coming down from Microsoft.
It really didn’t have a purpose to them. People bounced in and out of clans, and it just didn’t have a purpose. It was just as you said, a second friends list. If you wanted to play with those people, just send them a friend request.
It really caused a lot of issues with the constant spam of “join my clan” messages, and random hierarchy usually headed by some kid who wanted to be in control, and call himself a “Clan Leader”, along side his friend who wanted to call himself a “Co-Leader”.
Now, there are some Clans that serve a good purpose. I’ve heard of groups that are for girl-gamers only, or for older (40+) gamers, as it provides them an atmosphere they can be comfortable in. But they just adapted, and became groups. They didn’t need a clan level, or a hierarchy system, or titles, etc. They were a group of people who just wanted to play together.
Halo 2’s clan system promoted the bad kind of clans, with ranks, roles, permissions, etc.
In my opinion, Clans should be a 3rd party outside of games, instead of gaming revolve around them. Use them as a way to come together and find friends of equivalent tastes, not be under the command of some kid online who is going to tell you what armor color and emblem you have to use.
It’s just that as soon as a “clan” reaches more than like 6 people, it stops being “this is my selective group of skilled players that I enjoy teaming with” and instead becomes a huge hang-out and brag zone. Most just get members to have more members, without any real requirements.
I would be all for it if it was simply in the game for social purposes (why not?), but when you get into clan matches, playlists, etc. things just get a little ridiculous. BF3 and CoD seem to be working well with their new Clan system.