The OP must be kidding. Berdych is basically a talentless and mentally weak baseliner.
Why not come up with truly talented players who underachieved? Guys with tons of innate talent:
Mecir
Leconte
Gerulaitus
Santoro
Dogopolov
The top of the list should be Ivan Lendl, who choked endless slams against inferior competition: Edberg, Becker and especially Cash. Ivan had limited talent, but worked like a dog and was consistent beyond belief.
Berdych is a mindless drone out there. Horrible to watch and a complete a-hole in person.