Even though PGI have already their own concept about the clans (they must have, or they can totally forget adding the clans), i would love to present mine.
Clans are meant to be the best warriors.
So first of all you need at least 500 matches and a KDr of 1.0 or higher to be able to activate clans. The KDr will be removed after one week because of all the crying on the forum.
After you activate the clans you get a second character on your account, and you can switch between these two. First you have to do is a trial of position. You have to play against 3 GM/Devs or selected players. Only if you are able to beat at least one, you can play clans. If you fail you can try again in 3 month. This will be changed to 2 weeks after the next forum storm.
There is no ranking or ELO or weight match making at all. If you want to be clanner, you have to be able to handle all settings.
There are two modes to play against IS (against other clans its just 5vs5). Hard mode and easy mode. In Hard mode you will be paired in a 5 vs 12 match. On easy mode you will be in a 5 vs 8 match. The reward is 3 times higher in the hard match compared to easy.
Later there will be a batchal mode. Where two binary stars are in a lobby and bidding against each other who has the right to fight.
There are no credits on the clan side (money does not matter for clan warriors). Instead there is a honor value. You get honor points for clan correct, honorright bahavior in the fights. And for killing enemies. As well as winning a match.
1 for winning, 1 per kill (if no one else damaged the opponent while you fought him). -1 if you damage a mech that is in a fight with someone else, unless he attacked you, 3 for honorable bahavior. Like not attacking other mechs that are already in a fight, accepting a duel against a much heavier mech and winning, ...
You dont get any if you lose. And it does not matter if the opponent respect the honor levels. Clans stand over these barbarians from the inner shpere.
And dont come up with honor level 4 and how the wolfes have done it. This is not the clan way. Its only they want to win. They just want to win and dont gain honor in it. Sure, you can do it this way, but you dont get much from it other than the win

.
These honor points are to unlock weapons, mechs and equipment. And as well for the mech upgrades like the current ones.
They can be expensive, like 1000+ for mechs. Will be changed to 200+ after the next whining wave.
Downside on this is and bonus for the IS. When you fight against IS and you lose, the IS get salvage of all non destroyed clan tech and mechs. Randomly between the players that are still not dropped to the end. These clan tech can be used by the IS. But if it is destroyed in a match its gone from their inventory. This way its even possible that someone can obtain a clan omni mech. But use it only with the risk of losing the mech.
Means really high risk on hard mode that you stuff up the IS side.