My question is when employer is documenting the employee for evaluations and then they poke at things like shakiness, flushed face, nervousness should that be a just a reason to give them an unsatisfactory evaluation and is it more correct to evaluate them based off of their productivity then these characteristics?
A performance review is for performance review. It's hard to say if shakiness, flushed face and nervousness impact the employees performance. It depends.
If it's Alice from Accounting, who turns red like a lobster and is terribly nervous when spoken to privately in her lunch break, then NO. This has nothing to do with her accounting job.
If it's Marc from Marketing, who was a nervous wreck at the main press conference where he was to present the new product model? YES, that was not his best performance then.
You will have to figure that out for yourself, depending on the job in question.