Man, does it suck not having any recording software to show this off.
Sonic is pretty amazing when it comes to edge guarding. His new DSmash is particularly effective in pushing opponents off the stage following their second jump, though only if they are a certain height from below the stage, and timed perfectly. Depending on what their recovery may be, they may or may not be able to make it back. It's fairly difficult to pull off, but you can get some cheap, early kills off the likes of Mario, Luigi, Peach, and a number of others lacking great distance or a horizontally focused recovery that way.
How to do it? Simple jabs, a forward smash, and down tilt are all preferable tactics to set up the edge guard. Don't bother with his dash attack or any of his specials; there's too much ending lag with the latter, and too much vertical knockback for the former for either to be effective.
I thought I'd share this info with you guys in order to help determine if there is any effectiveness in such a meta game. I think there is, but it ultimately depends on who Sonic is up against. If this tactic proves cheap enough, it would definitely help his meta game immensely, and it's already looking pretty fine as is.
A few others I noticed? Mario is fairly balanced and in spite of that edge guard setup I discovered while playing as Sonic (I managed to kill Mario when he was merely in the 20% range with this tactic for crying out loud), Mario also appears to have quite a few tactics designed to control the field against Sonic, particularly with his neutral and side specials. Granted, it's not a terribly advantageous setup since Sonic's gameplan is designed to stall out an exploit openings quickly and effectively, while evading traps and setups from other characters; that gameplan was what got Sonic out of the gutter in Brawl, and now his buffs actually make him useful in delivering kills for once. In other words, Mario and Sonic appear to have an even matchup once again (though if anything, it'd suggest that both characters are competitively viable.
Luigi has some decent priority moves but other than that, he lacks kill options substantially, unless of course you decide to apply his infamous down taunt spike and the sweet spot in his recovery as decent kill options, and even then, I only applied the latter once or twice, with the former not at all. The nerfs in his power and knockback in addition to the larger blast zones have made him an almost completely useless character once again. Even his custom moves can't save him.
Bowser has quite a bit of startup and end lag in his moves. Granted, he's a good character, but I think at best, he's looking at somewhere near the bottom of the high tier list. Same with Little Mac, though to be fair, at least Little Mac has some pretty hard counters against some competitively viable characters still; lightweights, brawlers, and in particular, Rosalina, are all pretty weak against him. However, Pit and Dark Pit have huge advantages against him as well.
At the end of the day, tier lists are going to be a lot tougher to figure out--especially after custom moves are taken into consideration. With that said, here's what I think the tier list might--MIGHT--actually look like:
Top Tier (4):
High Tier (6):
High-Mid Tier (8):
Mid Tier (14):
Mid-Low Tier (10):
Low Tier (6):
Bottom Tier (3):