Re: Captain of the next Trek series
It all depends on what they did with it, but haven't as you already point out had characters exploring what it means to be human to various degrees. Would we not be retreating old ground.
You could for example set it on a ship operating a few years beyond the Federation border, who's Captain is killed and the XO has to step up. Some people can make excellent number twos but struggle when it comes to the next step up.
On the continent of wild endeavour in the mountains of solace and solitude there stood the citadel of the time lords, the oldest and most mighty race in the universe looking down on the galaxies below sworn never to interfere only to watch.