He lost the most times to Tomas, so no, you don't make sense, that can't be the easiest one. Kolya is not in form, Marin is on the up, but still not at his best. All three fairly difficult matches.
H2H doesnt tell you everything if you dont look at the location. 3 of them (paris, basel, dc) were on super fast surfaces. wawrinka is terrible on those. he'd probably lose to any top 50 who is decent indoors.
AO was when wawrinka's form was terrible.
davydenko will start finding range sooner or later, i'm inclined to think sooner. his game is the most dangerous for stan + it'll be his 1st match.
cilic's form is monstrous recently, even winning a TB against soderling ffs.
if wawa makes it to the 4th and plays berdych i am very certain he will win.