I had the same feeling. It was almost like experiencing the uncanny valley, which is odd because I sincerely doubt he was CGI. Nimoy is just old, now. I think it's awesome that he came back to continue/reprise the role. But something about his appearance was... off. It's not a kind analogy, but what I was reminded of was an open casket viewing where the decedent may look good, but something is just not quite right because the mortician didn't know them in life and prepared the body subtly wrong.