That's because the production team didn't know how to properly build, fit, or light the suit. It's about a failure in execution, not design.
Far too often, recreations of older productions tend to look like bad fanfilms, because the people involved don't know all the tricks that made the original look "right".
And, subjective or not, anyone who says that the Vader of THE EMPIRE STRIKES BACK, in particular (what with Peter Suschitzky's gorgeous cinematography) isn't of the best-looking characters in the history of film is nuts.
On a related note, people whine about how dated the original Enterprise bridge looks, but that design is perfect and timeless. Just rebuild the set with modern materials, and use modern cinematography, and it would look fantastic.