With the exception of the car escape intro, I play on 'Hard' and it's still too easy, but then again I'm not a 'run and gun' idiot and I try and use brains and tactics before heading into a fight. The best fights are the ones where they never even knew you were there.
I wish there was a new game + or 'extreme' difficulty where they increased, not the hit points needed to kill someone (because I'm of the opinion 1 hit, 1 kill) but more many more enemies, and more women and even children amongst them. After all, the cult's taken entire families into it's religious nonsense. So the idiots we need to rid the world of would include women and children.
Use Cheeseburger the bear!
While using cheeseburger the bear as your gun for hire, it pretty much makes the game easy mode! Because of his aggro taking and tanking abilities!
He is a tank, which means he will take all the Agro and receive all the damage which leaves you totally open and on her to deal a whole bunch of damage in return!
Just watch out if cheeseburger dies, you'll have to revive him, at least the revived process is like 2 seconds!
Long story short, you cheeseburger the bear and you won't have these problems anymore!
If anything I find the game too easy on all difficulties, I can just go rambo into a an enemy outpost and never die unless I get hit by a massive explosion or something. Seriously the amount of damage I can take before going down is insane, I basically never use medkits and I've only unlocked the first extra health perk, it's ridiculous.
Combat in this game just doesn't feel like a challenge, not to mention those 'judge' animals seem to be broken since they don't even attack me even when I'm front of them. In FC4 on the highest difficulty it was tough, helicopters did massive damage and late game snipers could two-shot you, they need to do some seriously re-balancing.