I prefer girls/women like Jeri Ellsworth. Naomi Wu looks like she had a multiple plastic surgery. She might be good at 3d printing.
In terms of pure engineering skills, I think Micah Elizabeth Scott is the one to watch right now. Not only does she do 3D printing and other mechanical engineering, she also does a lot of embedded development and hacking, machine vision using GPUs, as well as system design and integration. All that to assist in playing with her pet cat. If that's not an example of an engineer at heart, I don't know what is...
What I would like to see is TastyPC, CaitlinV3, or Joanne Chiang (all of them are models who enjoy building computers and gaming) getting (more) into DIY electronics and 3D printing, most likely relating to case modding. They would do well for those who think Naomi Wu shows off a bit too much or is a bit too skinny. (Side note: when I showed my cousin a video of Naomi, he thought she was Japanese! It says a lot when a Chinese guy makes that mistake...)
Something else that might be interesting would be a collaboration live stream with Dave and Naomi. At the least, when Dave plays professor like he often does, he'll have someone to play student, albeit more balanced since Naomi has more experience on the art side of things. Maybe more like a professor and a TA, with the audience playing the role of students.