Yeah, the traditional transition out of a failed gogoplata is an omoplata, then into a triangle again.
I see what you're saying. You really wouldn't have to pull up on his head anyways as the mat is already there to keep them in place. Post out your arms for base and drive your hps forward and all your weight is going through your shin, through the guys throat and into the floor.
By the looks of it, it doesn't look like Aoki was able to completely clear his leg from the over his opponent's arm. While not completely tap-inducing as stacking his knee on his ankle, in the unlikely event that the guy on the bottom squirms out Aoki can transition to a whole slew of other subs with his opponent's arm extended past his hip.
From the top, the armbar settup is really easy if you can't totally clear the arm.