Amy's design is absolutely awesome. The rest I think go a bit too far away from the original styles. If anything, looking at that reinforces my hope that they utilize a similar style to Gravity Falls, as I see a lot of that in his version of Amy. Get a few writers from Adventure Time on there, and you've got the perfect blend of AoStH goofiness with a few elements of SatAM and OVA seriousness. With the animation renaissance these past 5 or so years, I have no doubt there's a huge opportunity for Sonic to finally have a unanimously great animated show.
