It's sad just cause he brought to life such a memorable character, and was by far the best and only consistently great part of the original series. I'd think Shatner is probably just a little bit insecure about Nimoy's death being a bigger deal than his will be as he was super jealous about how much fans loved him when the show was on, probably due to Spock having much better lines and humor.
At least Nimoy had a full life and went in as happy and dignified way as we can all hope.