Jess Bush Chapel could have been a whole new character. People thought Padme dieing of a broken heart was bad in the star wars prequels, well I wonder how the reaction will be when we see this Chapel turn into the mousy shy easy to erase Chapel from TOS. Who does not even become part of the core 7 characters. I do think this may be hard but Jess Bush may have the acting chops to pull it off.
Paul Wesley does not have the charm or stage presence as Shatner. This has been discussed to ages.
Ethan Peck's Spock is okay but unlike Zachary Quinto, he does not come off as a natural actor. You can tell Peck is acting in the role. However I think Peck may be getting a pass because he is the most sexualised Spock and he is quite handsome, However Quinto too was handsome but he could act and show more range.
Ceeling Gooding, I believe should have been a whole new character. I have read some of the actress interviews and it is clear the show wanted to give her liberty to play the character as she pleased, though this may have served better as a new character. we could also have used some less TOS Character overall.
Mount is an Okay as Pike, but he lacks the commanding presence of TOS Pike. Bruce Greenwood is the best actor to play Pike.
We wiill have to wait for Bones, Sulu, Checkov and Scotty.
The bar I will say is high since Karl Urban was so good as Bones and John Cho was a bad ass Sulu. I know this is a streaming show and they get z list actors for this kind of shows, however I do hope when they cast legacy characters like Bones or Sulu, they cast actors that have some resemblance to the older actors as well as the acting chops to go with it.
