After some experimentation, looks like Vanney has found the magic formula, at least for now.
On paper it's suppose to be a 4-4-2 diamond, but it really is a hybrid 4-1-3-1-1 formation.
The key player is, of course, Giovinco, who is playing somewhere between AM and withdrawn striker role, and also has a free role to drift anywhere on the attack. He'll drop deep to receive the ball, but he'll also drift left.
This, combined with Bradley who is playing more of a supporting AM role instead of a playmaker role, plays almost a box to box role, but not quite that he doesn't drop back to help with defending as much as he used to. Bradley has slightly less free role, but has permission to drop back to get the ball in the mid, and stays more or less centrally. He harries opposition DM and CBs from AM position.
What's causing havoc on opposition defence is that man marking becomes harder with Giovinco drifting left or deep and Bradley dropping deep on offence, forcing defenders and DM to switch marking assignments. What's gotten better for TFC is that Giovinco and Bradley are developing good understanding with each other, and they sync their movements more, forcing opposition defence to lose shape. This causes gaps that other supporting players are exploiting better, especially the CF.
All this cannot happen without Cheyrou being a stud at DM, playing a deep lying playmaker role with good long passing, as well as being responsible defensively. And whoever 2 other supporting CMs are, they are playing almost interchangeable, helping out the fullbacks on defence on the flanks, but making sensible runs and supporting passes on the offence. The RB problem has luckily gone away with Ashtone Morgan finding new life at LB and Justin Morrow being adept at RB as much as he is at LB. Both fullbacks are making good overlapping runs and smart ones too. (IE Morrow's goal vs SJ when both fullbacks were on overlapping runs) Fullbacks are having more freedom to pick and choose their runs because Cheyrou and the 2 CBs are much more solid defensively lately.
Every player seems to be so much more comfortable with one touch passing which allows even fringe players to escape pressure from opposition when pressed. So, opposition can't concentrate on just few players, because the supporting TFC attackers are becoming better at exploiting space.
While it's still early in the season, and couple of key injuries and absence will likely have Vanney revert to much more conservative and counter based on flat 4-4-2, but this TFC offence fueled by Giovinco's dynamic abilities is causing a lot of problems for opposition offence.