Nimoy's voice is way sexxxxyyy.
He's great in TAS, TMP, is not phoning it in at any stage, or bored, he's just you know acting and showing Spock at the different stages in his life as an interesting character.
And no he was not so overawed by the 'great' Patrick Stewart in UNIFICATION that he was not Spock-like. I think any deficiencies you may see in his performance there are due to the TOS-hating producers/writers of TNG. Spock had to admit he was wrong and Picard and Data were great because it was well their show. Yes in UNIFICATION Spock was made out to be a fool, in RELICS so was Scotty, and in the first episode McCoy just admired the pants of Data. What do you expect from Berman?