Yeah, you are right. I also thing that he looks quite well from the side, but the "current Geralt texture" combined with the old head gives him a very weird look. I was very surprised that it even fit him (I did not need to change anything about the texture). Since I still find it interesting to have the possibility of "another Geralt" (as an example for mods that show him as a very young Witcher), I will try to work on the texture a bit.
A greater problem would be that the head has no "face bones", which means he is not able of facial animation. Sure, Geralt is not Jim Carrey, but it still shows. Another Redkit modder called Tekoppar might be able to help me, since he knows a lot more about this stuff.
Edit: Current progress (he still looks a bit weird tough)