Paul Wesley's performance certainly isn't Shatnerian (nor should it be), but I thought he was charming in his own right. May he play an endless procession of alternate Kirks.
The writers showed remarkable restraint in not bringing in Spiner to play Adam Soong.
One thing I did not care for was the official conflation of the Department of Temporal Investigations and Voyager's time cops. I prefer those being separate entities, with DTI being a fairly boring Federation department that interrogates time travel adventures. A minor thing, and that ship sailed in the fandom long ago, so I will let it go.