I'm not a big MP person (and typically despise PvP), but those of you that see this as interesting should really look at joining us on Saturdays when we play this mod.
Everything we do is COOP and all of us that make missions try to make them interesting and not just "go to A, destroy B, mission accomplished." I usually have a story line of the situation, insertions, extractions, multiple objectives, and lulls in the action (typically patrols where you don't know what's gonna happen) built into my missions.