The 5 stars are for the film 'Watership Down', not the critic. Critics like GB tend to forget Hubley's style did not go beyond iconic abstraction (Gerald McBoing-Boing, Moonbird, Rooty Toot Toot); excellent for the mythic beginning of 'Watership Down' but not realistic enough for what the rest of the movie demanded. If Martin Rosen's wisely chosen natural character designs are considered "crude" by this critic, then I can only say designs by Hubley would have seemed even cruder to a theater audience expecting something more lush than a limited TV animation style.
'Watership Down' was one of the best animated films to come out of the late '70's, bravely mixing environmental and spiritual themes while not condescending to children about the realities of life in the wild. This film is for children 8 yrs & up but definitely NOT for young toddlers. It is fairly faithful to the epic novel as much as an over hour & a half film can be.
The music of 'Watership Down' stands among the best soundtracks in the history of animated film, thanks to composer Angela Morley. 'Watership Down' has, officially or unofficially, become the 'Bambi' of Generation X & beyond. This was why animation legend Chuck Jones bought much of the art from this movie as he could before he died. He knew a modern classic when he saw it.