Im a little late for this but i think im gonna try this out
Although i may just end up doing co-op with a friend cause thats always funner.

Just beat it on Legendary, and had some trouble with the MAC Gun part. I ended up just hiding underneath the gun until the exact moment to fire, haha, and I did it with barely being hit. Next I'm gonna try and do it all without dying a single time.

Definitely the most difficult campaign after ODST

I really hope that that is sarcasm or that you got "difficult" mixed up with "easy".

The campaign was super difficult for me alone on Legendary, possible, but difficult