Hmm...
...sounds pretty complicated to me.
Since (as I think) CB will be skill based and not experience -> lvl based .. how about this approach:
First.. what do we want. We want to reward the players for forming parties/groups and fight opponents as a team. Besides being inherently a good thing to gang up on tough meanies we want to add something to it.
One problem I see is, that, due to the skill approach, you can only advance in a skill by using it. So beginning players can\'t (and shouldn\'t be able to) just tag along with a group of veterans, doing nothing but increasing in skill in any of his combat skills.
So what can be the (extra) reward for being in a team then - since we ruled faster skill increase out.
Hmm...
Better item drops (i.e. bonus on a hypothetical item drop table) - if somthing like that exists. Tho I wonder where those rats or ghosts carry all this items they drop in other games sometimes. So maybe we won\'t have those ... just hides, teeth, horns, wings etc. of the slain monsters to sell.
Maybe it would be nice to add just this:
A skill about acting in a small combat unit .. lats call it tactics. This skill would increase for every member while defeating monsters in a group by anyone. Being active or not (since observing a good team also gives some experience).
The benefint of such a tactics skill may be that it allows in combination with other skills to unlock certain special moves / spells / skills.
So maybe healing magics + tactics allows for a group heal, combat skills + tactics may give bonusses when two or more characters are fighting against the same monster (or maybe some special double strikes .. so it would be surely a hell to implement) etc....
So you get a skill increase for being in a party (tactics) and you will be able to unlock abilities you won\'t have otherwise....
all to benefit the community increasing partying (hmmm party

) - without (hopefully) unbalancing the game ... or for allowing the newbie - pushup.
just my two rubies on that.