you know i would really love it if they had a neko majin other than korin somewhere in the game. obviously they would never ever be part of the main game but i think it would be fun to see a picture of Z painted on the side of a building somewhere. it would be a nice throw back to a great manga.
I'm sure there will be some easter egg appearances in DBO. Maybe appearances from character or locations from the DB manga or others that AT has made. I'd like to see some characters from Sand Land :)
well as everyone knows goku made an appearance in Dr. Slump and recently arale made an appearance in DBZ Budokai Tenkaichi 3 as a playable character, akira toriyama will most likely throw in just about all his characters at one point or another, possibly in some side quests where the time machine gets thrown off course and end up in some of his other mangas and/or games, possible even some DragonQuest Characters
well i dont know if they would take it that far. but i would be more than happy with being able to buy a t-shirt in the shop that says TURBO on it, or if they had a tree stump with a sign on it that says "do not touch" in a wooded area that you might just stumble upon if you are out exploring.