Well, whenever i play someone that's atleast in the top 30 or so, all i see from them is massive blobs of volks + obersoldaten or some other crap.
My AT's constantly play against amazing allies players who do the same stuff as mid tier players, they just have far far better micro.
The amount of strats in this game is fairly limited no matter what faction you play, what seals the deal and makes you a top rank player is good micro and proper counter play. Some good players make use of not often used units (Sib's use of Ostheer sniper, I try and use Sturmtigers, ect.) which can really help blind side your opponent, but ultimately what's going to allow you to win over your opponent is proper unit placement and preservation.