Sonic in ssb4: shield-cancelling side-B:
I expect shield cancels, although they might be different. They have shown both side-B and down-B.
It's hard to tell from the video they've shown, but it looks like the side-B startup frames are quickened. Compare:
http://www.youtube.com/watch?v=T7w5XUPHFoY&list=PLA1lIms2gwaDnOFGXUXtLj8KW5A4qNiKI&t=29s
vs. the frames I talk about here:
http://www.youtube.com/watch?v=vQ34M-Bdo6k&t=7m20s
During Brawl side-B startup, Sonic ducks his head, and for maybe a couple frames is spinning as a recognizable figure (you can see his shoes, head), and then at a specific frame he turns into an amorphous blue "spinning circle-saw". The first frame he's the amorphous-ball is the first frame you could be a shield instead (and if you did Grab (= shield + attack) input before that frame, it would have buffered a shield instead of letting you actually grab. That's why if you hit side-B and you want to grab, you have to wait a few frames before entering grab-input.)
In the new video, youtube doesn't give enough frames to tell but it looks like that startup-phase is almost gone. He crouches, and then is the amorphous-ball. So if we can shield-cancel that, either it can happen earlier, or it's not visibly obvious when it can happen.
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Sonic in ssb4: other observations
In their video they don't seem to have changed Sonic himself at all, aside from a new look and the general physics being tweaked (actions look more sharp/discrete to me, but most of the attacks they show are so poorly spaced it's hard to tell anything about hitboxes (should we start calling them hitcircles in smash?)).
The video reveals lots of the usual side-B/down-B mechanics:
- down-B charges in-place, flashing big circles around to show how much charge)
- side-B pulls backwards while charging
- side-B and down-B transition to SDR on the ground, which transitions to ASC if he rolls off a ledge, which transitions to SDR on the ground, and landing onto the ground can sometimes do an instant SDR-turnaround
- the blue trail behind the spindash is still a thing, and probably still indicates whether or not the hitbox is active. If that's the case then we see again that SDR-turnaround has no hitbox.
- hitting stuff / going uphill in spindash slows it down which can shorten the length of time an SDR lasts
- screech-stop lag still sucks
- we can just baaaarely see that SDJ is still a thing, although they turn it into an up-air veeeery quickly. I'd love to believe that's an actual SDJ-becoming-a-Uair (which you can't do in Brawl), but I bet instead they were just jumping out of it and doing the Uair immediately. I don't think we can tell; he springs afterwards which doesn't tell us if Sonic still had a second jump after the Uair.
- no sign of VSDJ, or if SDJ has a hitbox, yet. Also very little information about ASC, no reason to believe it's any different yet.
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Other thoughts on ssb4:
It looks to me like they did a rather direct port of Brawl to Wii-U (does that even require a "port"? Maybe just a recompile? lol), i.e. they're starting from there and tweaking the mechanics to suit the minor, but intentional, change in style.
I expect it will be a lot like Brawl but with many of the glitches fixed, and hopefully a whole new set of glitches (to keep things interesting!!) What the heck would smash be without detail or nuance?? I have trouble imagining Brawl without:
- spinshot
- grab Sonic/Snake out of up-B glitch
- side-B-on-slope perpetual-invincibility
- side-B and up-smash invincibility frames (because who knows if they'll keep them)
- momentum-cancelling / bucket-braking
- grab-release / chaingrab gimmicks
Maybe this time, SDR will restore 2nd-jump data. Because I'm convinced that was an error. At the very least it was really stupid / confusing.