Was once Sonic Adventure 3

Sonic Unleased or Sonic World Adventure was once planned as Sonic Adventure 3. It was going to have Sonic, Tails, Amy, Knuckles, and Shadow as the playable characters. Shadow and Knuckles were later dropped and Amy and Tails were dropped as playables to NPCs. the people at SEGA changed their minds on making it SA3 and decided to add in the werehog and make it a standalone title.

I like the Sonic Stages in this game they were fast paced and fun. I wonder how the other four would have played? Shadow most likely a Sonic clone or in Werehog esq. stages, Knuckles would probably have played similar to his Treasure Hunting stages from the first two, Amy the same as 06 and the Adventure games, not to sure on what Tails would have played liked. I'm also kinda glad this didn't become an Adventure game.
Justin said:
Source please. Only info I've seen that people have speculated is the japanese title being "Sonic World Adventure", which would make sense since he actually does adventure the world in the game.
Its not from one specific source I found it from all over. The game was planned to be SA3 but that never got past maybe concept sketches and ideas during the design stage of the game.