I like the changes made to 2.5 Sonic, but I honestly don't think it's enough. It's certainly too early to make a full judgement, but there are two moves that, in my opinion, make him feel very unlike a Melee character. Down B and Neutral B. These moves aren't necessarily broken or overpowered, but their design doesn't jive well with the rest of the cast, and may be the cause of the polarizing attitude towards him.
Homing Attack fails on two levels; it's almost impossible to gauge when it will certainly hit or not, and it locks on. Samus has guided missiles, but these moves are on very different levels. I don't think there should be a move that guarantees a hit in such a way. My proposed change is that Neutral B should always just be Blast Attack (which is currently B, A). The way the move works when it hits would be the same, but it would have a set, reliable trajectory that isn't as guaranteed out of combos.
Down B serves the same purpose that Side B served in Demo 2.1. It is too effective and disruptive, and people who understand the character exploit it as much as possible. It has basically become a substitute for running. I suggest that Down B should only cause Sonic to spin in place. It could be charged up and have the same damage effects as in 2.5 (still can be shield canceled), but wouldn't cause Sonic to shoot forward when released. This would allow pressure somewhat similar too a shine, but instead of knocking characters back a certain distance, it would provide multiple hits (and possibly a follow-up grab as I've seen a number of players implement already).
These two moves aside, I think Sonic is really solid. I think the buffs/tweaks he's received in other areas make him a really strong contender, and I think these changes would help develop him more in that direction.
I know some of you Sonic players are really attached to the play-style I'm arguing against, and it's too early to say anything for certain, but I've been considering this since 2.1. Sonic's current design is certainly unique, but I don't think it's beneficial for Project M overall.