The first thing I noticed are:
1. The shape of the mouth and the lips. Michael Dorn has very full lips and the figure's lips are too thin and shaped incorrectly.
2. The nose is off. The curvature of the nostrils and the shape of the nose need to be adjusted.
3. The eyes: Worf's character is defined in part by his eyes (Worf always has a proverbial fire in his eyes and sometimes looks downright angry or extremely concerned about everything going on around him). The eyes probably need to be a bit closer to the bridge of his nose, slightly wider, and the size of the pupils adjusted.
4. The brow and forehead shape needs to be adjusted. The ridges are very prominent and the prototype is lacking this a bit.
5. Worf's hair. If QMx is going to go with rooted hair, then the hair needs to be able to easily cover the ears as we don't usually see most of Worf's ears.
6. The moustache on Worf is quite long and usually hangs over the rest of his beard.
7. Body height and shape. Worf is four inches taller than Picard and Data. He also has broad shoulders and a heavier set upper body...this is a Klingon warrior with a prominent stature!
8. The uniform. The uniform shirt should fit more snuggly on him due to his muscles as much as you can get away with without sacrificing articulation...you know everyone is going to pose him with his bat'leth.