The characters were paper-thin enough when portrayed by actors on film, thanks...
Only if by "paper thin" you mean better-fleshed-out-and-well-rounded-after-a-mere-13-week-run-than-"Enterprise"-managed-to-accomplish-in-4-seasons
Eh. Comparing to Enterprise feels a little like beating up a quadriplegic. How about Stargate SG-1, Battlestar Galactica, or Babylon 5? The claim is still true, but it doesn't look like Firefly feigned a disability in order to compete in the special olympics.