a campaign manager is supposed to read many of the posts made in his campaigns. That's a great opportunity to Merit the good ones (and remove the users with bad posts from the campaign). That's not Merit abuse, it's doing a good job.
Yes, that's very true, a campaign manager gives enough time to reading posts made by the users who are enrolled in the campaigns that he's managing, and thus it becomes easy for him to notice good posts. And, it's true that such campaign manager can merit all good posts in the campaigns that he's managing and there's nothing wrong in meriting good posts even if you're meriting someone who's part of the campaign that you're managing.
I believe Icopress can do both jobs brilliantly without any issue. We all know how much contribution he's doing on this forum and as a merit source he'll be able to contribute even more by sending merits to the posts that need those merits. I believe Icopress can be one of the best merit sources of this forum and that's why I think Theymos should definitely assigned him as a merit source.