Having worked in software all my life, I know that no feature is free. For them to have included three different playing modes, something else had to go. Instead of concentrating on a single gamestyle, the one that got them to the position they're now in, they're trying to be everything to everyone, and I seriously doubt they will pull it off. If I want a Space Marine Shooter, I'll kick over whichever rock 343 studios or Epic is currently under. I come to Bioware for the story.
No, the reason they're boring is because a) I don't give a shit about killing the same thing again and again, and again, and agian and again just to progress a few yards and do it again. and b) They don't progress the story at all. Their entire reason for existence to to pad the gameplay time.
And yes, I will be playing story mode. I did, in the demo, and there was _still_ too much boring run and gun. If I wanted a zombie survival game, I'd be playing Left 4 dead. I get it already, there are lots of husks. Whoo.