wow good find my man, Yesterday I was thinking after experimenting with it that this tech sucked but actaually later that day I tried on wi-fi, and man It worked great in short bursts. like Snakes Ftilt if shielded it moves you back, out of reach to counter making the shield useless, but if slid it counter acts the forward momentum allowing for a quick counter, and sometimes a perfect shield.
as for cancels and whatnot theres nothing there but it's great for approaching spammers and heavy attacks.
I'll retract what I said as far as online play goes, since you can't actually time shielding properly on wifi due to lag, neither can your opponent time the punishment properly (though I'd still suspect it's very weak against grabbing). During ordinary, lagless play, however, I would go so far as to say that simply walking toward your opponent and shielding at the last moment is
strictly better, provided you're good enough to actually do it. Ideally you'll deliberately powershield, but even if you shield a bit early, you'll still have the forward momentum from walking - and you get exactly the same effect described in the quote above, only without draining your shield or limiting your own options.
This thread is a very similar case: the technique described is not actually useful (exception: ICs get a nice desynch out of it), instead, the advantages observed simply arose from the fact that people were consciously deciding to walk toward their opponents rather than running. Walking is awesome - you can do anything from a walk, including turning around, using a tilt attack, a smash in any direction or even shielding when you have to.
Walk -> sheild
is useful. It's also nothing new. But shielding repetitively does nothing; if you're not under attack, using the shield just ties up your options and drains your shield. If there are projectiles coming at you, time your shields to powershield (or just shield) each one; in short, don't spam the button.