At this point we're just going to have to agree to disagree. I've played through RE4 several times, but I've never touched mercenaries because I didn't see the point. It's probably the same reason why I tend to play arcade games once or twice, once it starts feeling repetitive I quit. Invariably.

Multi-player games help alleviate the boredom of repetition, but it's not infallible unfortunately, just a matter of time until I tire of anything that is deprived of an interesting narrative.