Radovid looks exactly as he did in W2 (albeit with more polygons, enhanced shading and a fuller beard).
There's a very important detail there, his face is no longer symmetrical in TW3, look at his eyes. Asymmetrical face is associated with inborn genetic defects and developmental problems. Humans are very good at picking up asymmetries in the face because it's a part of an instinct of choosing a healthy mate for future offsprings.
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His shaky mental stability/paranoia as well as his resentment and viciousness towards witches was well established in TW2.
In TW2 Radovid had neither shaky mental stability nor paranoia. What happened there is Shilard revealed to him an information that his adviser Philippa and her Lodge are responsible for his father's death, supposedly with a proof. His reaction to such revelation (i.e. desire to execute all members of the Lodge) was normal for a medieval king. And mental problems don't pop out of the blue, they are usually persistent from childhood.