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.
I really feel like there was a lot more that could have been told with Data's story that ended up just kinda getting compressed or ignored altogether once they went to movies. And Worf really never tried to be human. He chose his Klingon heritage, mostly. What about that story of the Andorian zhen who has chosen a human path because of being raised by them, trying to live as human, but having the Andorian four gendered physiology and the responsibilities to the Andorian people that come with that? I might, just might, could see that working.
Another exception to my human only rule might be if they could bring back an alien character that they already made a general audience care about in a previous series as the lead. But I think that pretty much limits us to Captain Dax or maybe