I played Sonic in B+ for about 2 weeks, keeping up with updates...but too lazy to keep up with these B+ boards so forgive me if I go over something that has already been pointed out..and I can go on and on about Sonic but I plan to keep my visit here short so I'm only hitting on keypoints in Sonic gameplay.
I'm no known pro (yet) but I'am a tourney viable Sonic (now lol) in vBrawl, it just feels that you made two times faster but made him two times harder to play as and two times easier to kill.
He has the speed feel that I at least wished for in vBrawl which is a good thing, but You took too much away from Sonic.
For example, now projectile based Chars (Samus, Wolf, Falco, etc) now **** harder like never before when against me.
Spinshot is near useless now since he falls so fast, it used to be a great option for closing the gap when used right. but all I can do now is run&shield, which can get exploited easily by mindgaming a projectile into a grab, but If the Sonic knows this is coming he has to still keep distance and hope the opponent misjudges range and whiffs a throw (unlikely in high level play) while still (barely) dodging lazers...which keeps you still at bay and defeats the purpose of all the shielding running in the first place....I know you have to work for your kills in vBrawl but doing all that in B+ is ridiculous.
Nearly all his mindgame potential with hiz spinz flew out the window in B+, You might as well tear out your B button when using Sonic now. It's near useless to try and mindgame the spinz at high level. All that knock back and hitstun with spindash has now is near useless if you cant really get it to combo properly. Spindash to F-air in vbrawl was more consistent and easy to perform than it is now. It feels like I'm charging a oneshot cannon or a jigglypuff spin, like a onehit wonder move now that doesn't K.O.. Spinz was never that good of a approach but now it's even worse. Anyone with good DI sense or good sense in general could avoid almost any followup from it except just maybe U-air...which to me U-air is too good, the disjointed brokeness is funny in B+.
The momentum is something to be laughed a little because if Sonic's true speed was unleased when he jumped from running he would fly off the stage into the blastzone very quickly lol. But anyway That momentum is something that's wierd, it's probably something I have to get used to but It's harder to get into a gimping position offstage, I have to jump like three times early and let momentum carry me in order to not jump clear off the map and missing my chance of offstage/gimp play/chance.
It feels like you guys took away Sonic's "I hit you and Now catch me if you can" style play from him, and making him into a repititive agressive low priority Fox/CF mix minus the intense kill moves type character . Espy's gameplay videos in B+ proves my point in the agressiveness/repetitive area...It's like a "WTF is Sonic now" when watching him. Just dash dance to grab constantly to Nair and you win ...No matter how pretty the new dashdance looks...it's still wrong...
You should take a look at balancedBrawl's Sonic and mesh together. They didn't mess up the flow of Sonic but they did make him crappy as a character by under-powering him. I think the best thing they added to Sonic was making his spring sem-spike people.
TL;DR
As a strong Sonic Main I feel that:
Sonic just fails in Balanced Brawl, Sonic is a robot in B+, Sonic Sucks in vBrawl.
but to make Sonic better in B+:
Try to balance the ying and yang's of Sonic. Sonic is two playstyles in one. He is Spinbased and Run-based.
Power is not better in Sonic terms, Get rid of the spindash knockback, make his spindash usuable/combo-able again.
Make him a gimping god not a techchasing wonder.
Make the spring a spike lol.
edit: Oh and a Insta-Shield wouldn't hurt. lol
That's all I was able to find in the 2 weeks I've been playing.