My first playthrough was on hard without any stealth and it was awesome . Some fights were let's say rewarding , like shooutout with the old Halbech guy and his guards in Rome , or our favourite Russian junkie when you are not very powerful . Then I wanted to finish the game very fast on normal difficulty with recruit to unlock veteran but found it too easy and simply boring so I switched to hard anyway . I think every game is much more enjoyable on higher difficulty , especially the first playthrough.