The Archie fans are what we can best describe as the "idiot fanbase". Archie is just horrible. Anyway, here's my pick for ideal VO along with earlier roles, assuming the SLIGHT chance of new actors. My philosophy is to have a VO that fits the character's personality. Most of these VA come from either the Disgaea series or the Tales series, two series of RPGs that typically get good marks from critics in the VO department (applies more to Disgaea, which is praised for terrific voice acting).
1. Sonic: Yuri Lowenthal. Sasuke, Luke Von Fabre, Prince of Persia (1 and 3), Adell?. The last one is unknown since opinions are divided between three possible candidates. The majority opinion (not on imdb) of the Disgaea community on one of the great unsolved mysteries of the game is that Yuri is Adell's VA. When you think about it, Adell shares many of Sonic's personality traits (hot tempered, cocky/sarcastic, strong sense of justice, fighting style that emphasizes speed and mobility, cheerful demeanor, disdain for weapons, refuses to fight dirty no matter what) thus is perfect for an older Sonic.
2. Tails: Collen O'Shaugnessy. Genis Sage (once again similar character type).
3. Knuckles. Crispin Freeman. Overlord Zetta (Makai Kingdom version), Regal Bryant, Mathias, Itachi. Knuckles needs a real tough sounding voice. Steve Blum is also a good fit.
4. Amy: Kate Higgins. Arietta the Wild, Sakura
5. Shadow: David Humphrey.
6. Rouge: Michelle Ruff (Etna, for a more sarcastic, acid tongued Rouge) or Wendee Lee (Rozalyn, for a more manipulative, pompous Rouge).
7. Cream: Sandy Fox (Flonne, Marona) or Tara Strong.
8. Espio: Crispin Freeman or Steve Blum.
9. Charmy: Stephanie Sheh. Hanako, Princess Natallia, Hinata.
10. Dr. Eggman: Since I doubt it will be possible to get Mike Pollack without 4kids, my pick would be Michael McConnohie. Captain Gordon, Van Grants. Capable of doing both comical and serious characters.
11. Blaze: Kari Walgreen (Raine Sage) or Heather Halley (Tear Grants).