+1
I would like to contribute one tweak though Jas:
As you say, difficulty remains set from the start, either by selection or squad size.
But what if rewards were calculated at the end, only based on who Actually participates.

This way you don't divide a fixed total, you just give the rewards to each participant.  Each player receives the same nic and tokens, modified by a bonus calculated by the number of actual participants, regardless of mission difficulty!
And as you say Jas, this should be in the order of 20% on the high end.

Also, it might make more sense if we call this: "participation bonus".
The idea is that we want to make people participate in a group activity right?  Call it what it is.
We can make this bonus independent of the difficulty of the mission.  (this will encourage folks to more accurately select their difficulty on your slider jas)

Case1:
Squad member takes mission, no one else participates.  They only get reward for a 1-member squad participation/no bonus even if it was difficulty=10.  If no one participates, no bonus! (stops the exploit thing right?) 

Case2:
Squad member takes mission of difficulty 10, 10 members participate, Each of the 10 get a 10-member squad participation bonus.

Case3:
Squad member takes mission of difficulty 10, 100 members participate, Each of the 10 get a 10-member squad participation bonus.  Key here is that they have to participate.  Even if someone tried exploiting this with alts, they would spend more time micromanaging their participation making them run the mission slower anyway (my hypothesis anyway).

Would this help?

How many we need to point that out?

Nobody doing or incent to do misisons together. That is not encourage teamplay.

Well, in ETHOS, nobody does missions together, why? Because its not worth it. That is silly. Now, individiuall do something, if we would get rewards, we would do teamplay more, and do missions together.

                1 player       2 player          ...        10 players
NIC              x                   x*1,05                     x*1,05^10
relation         x                   x*1,05                    x*1,05^10
token            x                  x*1,05                     x*1,05^10

need to be increased if you do missions together, I dont see easiest way to incentives your playersbas, you seems like everywhere support teamplay, but the most used thing you are not.

Worst thing can happen, what happeend already LOL, with mission rewards. Then you can nerf it.

WORST thin you HAVE to leave squad at beta!

FUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU

Jasdemis analysis is missing being able to accept also lower level missions to be accomplished in the same walk.

Tried a new mission system ... Zoom ... you're kidding? I want to do the mission without leaving the squad!

WE want THIS: http://imgur.com/Os2deMJ

We want to do the mission, but do not want to leave the squad. Zoom, it's very easy!

Terms of payment will be applied not to the main squad - to "mission squad" inside main squad.

If I want to do a mission, I must to put a "X" in front of my nickname. And to all who are "X" - is used for missions payments system. As an alternative - there put the digit. Thus, it is possible within the main squad to make several squads for different missions.

OR simply enter the second squad. This payment system will be applied to him.

Break the perma squad Zoom!

Dont hold back!

When Indiana is mad, you know you messed up.

HOLY HELL!!!

This is still not adressed?

HIGHEST PRIORITY!!!

And make them playable in "TEAMS" (squad)