One thing to remember is that bulma has “naturally” blue/lavender hair. Her dad has hair that color, as do her children, as do *other* non-related characters in the anime like Maron. It is not meant to be a “weird” thing she did as a rebel kid. But if they dye her hair, in the “Real world” the impression will be that it is fake, not her natural hair color, unless a bunch of extras have weird hair, and it is not the sort of thing the audience just buys without an explanation. Same with cat/animal people like Puar or Shuu or Karin or scattered extras over DB that are catlike. (or talking pigs and turtles). They are standard in the DB world, but would require a lot of explanation to be accepted as “normal” in a movie.

OTOH, Piccolo *is* an alien and is weird in DB. Oozarus are weird. Goku is an alien. Those things are baffling to the audience, but they are meant to be baffling even to the ordinary DB world person. So they can be kept in. There are fantastical elements being kept because the story is fantastical. The world the fantastical story is set in, however, doesn’t need to be weirder than it has to be.

On chichi being the “it girl”:

Well, the political structure of the DB world is very different, mostly independent towns and and cities ruled by local kings or elected rulers. Chichi is the daughter of the Ox King, and had a huge wedding banquet, and was an important person in her town, and definitely very wealthy. Translating the whole political sort of serf-like system into the real world also is hard. People can understand “rich popular girl” more than “Daughter or powerful ruler of small faming community,” especially when so much of the DB world is so “high tech” otherwise.