Well I think most of this game mechanics are based on RNG heavily even how enemy target your team member is so randomly..
you can control enemy targetting though by using defensive servants like Mashu, or you can force enemy to attack someone by using Kiritsugu's Scapegoat
in the case of cards that provide effects with a 80% chance, you can rectify that with Ozy
Enkidu is just fucked because you will never know if his Buster UP will boost his quick or his arts
Quetzalcoatl, Gorgon and Taiga rate up starting soon, but DW can't bait me with this, I'm waiting for King Hassan (the most gar assassin).
if you follow me on twitter you might notice i pulled gorgon
i'll level her up once i'm done with babylonia