We used to have a bit more say in this, it’s mostly chosen by editorial now. One of the reasons I do a lot of small side things where possible is the opportunity to work with a wide variety of artists.
The main thing I look for is acting. Is the artist able to convey emotion through body language and facial expression? A lot of ‘hot’ artists really can’t.
Someone like Ed Benes or Nicola Scott, no matter WHAT wacky thing I ask for, they can draw it. They will put it on the page. It can be very frustrating, even with really fine artists, popular artists, when they can’t really convey subtle emotions.
Lots of comics artists are great at poses…the characters are always posing. I want them to look compelling when they AREN’T posing.