Quote from Xemnas;433871:
shadow warriors/fighters have the same AI
Not true. Yes, they have similarities, but Skeletons are much more cautious by nature than Shadow Warriors/Fighters. Shadow Warriors are also very Smash-happy and when they
do decide to do something else, it is very easy to tell whether it's Counterattack (they stand still; also, they rarely Counter at all) or Defense (they will continue to walk towards you even after coming within a certain range). Also, Smashing or knocking back an already aggro'd Shadow Warrior with anything but Windmill will make it run straight for you--this will even happen rarely after a Windmill. Shadow Warriors will also move in your general direction when they aren't committed to an attack 95% of the time. Shadow Fighters are closer to skeletons, but are more prone to running straight at you and/or cancelling their combos on you than Skeles. Their random movements are also considerably more random than a Skele's.
Skeletons, on the other hand, instinctively run away from you upon being aggro'd. This will go on for a few seconds before they start to strafe you and then they will run straight at you. Part-way through that attack, they will either stick with it or load Smash/Defense/Counter. It's hard to distinguish between Counter and Defense on a Skeleton because from afar, they will stop moving right on the borderline of your WM range. You generally have to run further away to determine if they'll move closer to you (Defense) or continue standing still (Counter). After being knocked down, a Skeleton who preps Defense or Counter in response will hold that stance for much less time than they normally would before resuming their strafe pattern. Skeletons never run straight at you after being knocked down (exceptions are armored skeletons in the higher Rabbie dungeons, who incidentally will also occasionally run straight at you upon aggro). This of course is in reference to Skeles who do not know Windmill. Skeles who do will almost always make that their go-to ability on knockdown; Skeletons also never use Windmill offensively.
Tl;dr: Shadow Warriors/Fighters have similarities with Skeletons in behavior AI, but they have some seriously major differences, far more than similarities.