HSV-1 is far more widespread, but I would struggle to call it "more malicious". It is a rare source of blindness, but for the most part is a fairly benign infection most people don't know they have.

HSV-2 on the other hand, has some serious consequences for congenital infections, and may result in easier acquisition of HIV.

Beyond that, research in HSV-2 should extend to HSV-1 fairly directly. If I had to pick one, I'd go with HSV-2.