Well I can totally see your point. Some of the characters aren't very Tamagotchi-like. I saw that there's a sheep available on V3. A sheep?
Not sure which Sumo guy you are referring to, but one of them is from the original Tamagotchi.
But I also think that like with V3, I'm sorta disappointed in the characters. It's basically many of the classics and soooooo many of the Mesu/Osu characters and so few are actually new.
Back in my day it used to be each new Tama had all new characters, nowadays they are recycling like crazy. They used to create new characters to fit the type of Tamagotchi. So in a way.. well I'm disappointed.