I'm not seeing what the big fuss is over the campaign being terrible. Its a lot better than 3's... its just frustrating at times.
There is one mission where you are in a tank, enemy tanks bust out of buildings behind you and can kill you while you're focused on AT soldiers or another tank.. so its one of those redundant, die, prepare for where the hidden tanks comes out from, die again and start all over and prepare for the first and second. die again, and start over. eventually you get to a check point where you get one tank and a BTR to try to take out 6-7 other tanks all trying to kill you at once... The game has ammo/equipment change stations ever 10 feet it seems because you never get enough ammo to make it though a mission. It takes way more bullets to kill someone than it does in multiplayer to make matters worse.
Back to the tank mission. I ended up having to damage a tank with my tank, jump out before my tank blew up and finish off the other tank with an rpg. I then had to run back to the ammo station, get more rockets and repeat. It takes 2 tank shells to kill a BTR and 4 for another tank, it takes 4 to kill your tank, sometimes 3. So its impossible to defeat all the armored vehicles with your two, not to mention as soon you try to run for the other one, you're getting lit up by 2 tanks. It was stupid I had to resort to an infinite RPG rocket cheap trick to pass this part of the mission, and RPGs don't act the same, the arc is huge, and i found my rockets going clear over the tanks unless i shot them from point blank.
Outside of this frustrating mission, the story is interesting so far. There are plenty of over the top moments, and more unrealistic unsurvivable falls and crashes than COD could ever dream of. The unlocks for multiplayer make it a desirable play through as well. The M412 Rex is unlocked in the first mission... with a damage of 65 for a pistol. Its worth at least booting up the campaign and playing the first 15.min.