That's DG theory (based on practical experience, of course). If you get an urge to comment with: "I'm gonna pwn you pathetic Sedna with no items and no brains, lololol n00b", please don't bother (:
In my opinion, there are three levels to understanding game dynamics, in ascending order of difficulty and rarity - player's level usually correlates:
(I) A tactical (fighting-game) level. Being able to put your guy's/girl's abilities to good use (correct skill timing, knowing when to chase and when to back, etc.) in any given combat situation. Typically, that's the level of understanding which distinguishes mids from noobs. [High mids also don't run from an allied Sedna/BS QoT even if the UB is after them and stay under the tower and attack in such situations instead of trying to run to the crystal, thus giving the UB the free kill.]
(II) A synergetical level. Map awareness (porting in), adapting to a matchup (e. g.: Sed and QoT fight Erb and Rook; Sed should always re-lane to face Erb, QoT should always re-lane to face Rook to achieve the best results). This level of understanding is usually reserved for pro players.
(III) A strategical level. A non-stop aggressive structure pushing is the single most important aspect of the game, as is flag control. If there was something I've learnt from many games with ppapanek, it's this. To my surprise, even extremely good players with superb map awareness often lack in this department. The only Western players who are 100% in this respect are pacov, nnnils, and - I do recall it very clearly - Nomilarac. The curious thing is, there are players that have better map awareness that those I named, and probably are also better tactically (well, not in nnnils' case). Still, in my experience, in skilled games, push/control orientation always pwnz kill orientation.