Shatner is uniformly terrific in early season 1. He's the viewpoint character, and he really carries the show, during the period before they fully flesh out Spock's character and before they establish the Bones banter. I think Shatner's early excellence is often forgotten by fans because of the direction he went in later – he starts doing his readings in a really broad way, sometimes using Spock & McCoy as straight men. This is very much true in the movies, also true in some of s3. A lot of fans hate his performance in Turnabout Intruder. Ok: but Shatner is serious business in s1, and he's a badass. It's almost a different show in s1, given the focus on Shatner and his intensity.