Biedrins is a potentially good player, but he does not have a very high ceiling. He lacks the size to be a dominant defender, and lacks the post moves and shooting to be a dominant scorer.
I can see him improving his post moves, but his horrible FT and jump shooting suggest he will never be an effective scorer outside of 8 feet.
What he does and his age justifies his contract- I just don't ever see him being a all star big.