While the shootyblasty lasers and explosions side of DB could easily be replicated with CGI, and the villains such as Cell and Buu and Frieza could be accomplished reasonably well with mo-cap the same way Gollum and the PoTA apes were, it's the more human characters that might be trickier, because there were various "shortcuts" and stylistic choices made for them that could be problematic simply because doing them live would potentially be a uncanny-valley human-but-not-quite situation.
First thing that comes to mind? Goku's hair. Not just the spikiness of it, but the shape of it, how it looks from different angles - all three of them.
That infamous silhouette exists only in those three forms - front, profile, and behind. His face moves but his hair does not. They're like how no matter which way Mickey Mouse's head is turned, his ears are always drawn like this -> O_O even though that's physically impossible.
Unless they also CGI his hair, how could live action replicate that without looking ridiculous? Vegeta is the same situation, if not worse, because he doesn't even have a second and third position - just a singular shape, a big black christmas-tree-shaped thing on his head, devoid of details to indicate anything three-dimensional. Some of the toys' attempts to figure that out have been comically absurd - I had an action-figure of Veggie as a kid that rendered his hair in such a way that while a facing-forward view was perfect, any angle other than straight-on looked downright bizarre - it was a smooth wedge-shaped shark-fin of black plastic with the back-side of it a lump of spikes resembling hiking-boot cleats.
And then there's the more "unique" things like Krillin's nasal absence, Tien's third eye, etc., that if done live action would likely also trigger the sensations of uncanny-valley due to them being humans with either something expected being absent, or something unexpected being present. Why do I say this? Well, heck, there's actually been studies where photos of very well known people like media celebrities, sports figures, and political personalities were slightly edited to have minor-sounding changes like having teeth reshaped or eyebrows removed, basically minimally altering parts most people wouldn't normally pay attention to consciously, and people reported the images made them strangely ill at ease until the changes were pointed out. When the changes were deliberately exaggerated to be obvious, nobody reported the unsettling sensation, only when the figures were "not quite right".
"Let's see... There are monkeys that evolved into men and monkeys that didn't. Just as well, there are men that remained men and men that evolved into something else. Do you really think humans are the ultimate form of evolution? How arrogant."
-- Kakurine, Evil Zone for PS1
