In fairness, people usually change quite a bit over a 10 year period. Spock, as played by Nimoy, even evolved over time. Of course, he had life-death-life to help with some of that!
If we do not see Spock after this season, how will we accertain his level of maturity 10 years hence?
Ethan is doing a good job so far. I am eager to see how new Spock looks without the beard and in a TOS style uniform.
He spent 10 years growing and becoming a full commander and XO. Maturity coming with age and all that jazz. Kind of like how we figured out Kirk became an admiral in TMP.
I'm sure we'll see him clean-shaven, bowl-cutted and in his Disco-TOS blue uniform in the final episode.