It exists the possibility that, as it is now, in the near future there is a problem with the Antagonist.
On the one hand, as some have commented, the rewards should be much better depending on the level of the antagonist and definitely better if there is an antagonist or not.
I have found that it can happen that when playing cooperative if a player int hte team does not perform very well is easy to lose against a more or less good antagonist, then people who have a good level will tend to play more as an antagonist, so new players will have an added difficulty and more possibility to be frustrated as it becomes difficult to successfully complete any mission. I think it will be vital that the matchmaking is really equitable or at the end the noobs will play mainly coop and become easily frustated and the elite mainly only as antagonist.