To be honest, I'm not so sure about the whole "no personality traits" thing. Whether your retro-vibe space tiger is an adventurous space base raider, a travelling space merchant or a crazy space inventor can make a lot of difference in what said retro-vibe space tiger might look like. The artist of course doesn't have to know that there's a retro-vibe space tiger's cousin's brother's roommate that has a genuine imitation schwartz ring. That's just too much detail. But surely the big driving forces behind the character can help with the design.

You can definitely use some adjectives to help for a character's mood, but really for character design, it's the visual information I'm most interested in. A single sentence like "they are very sassy and flirty" in reference for a pose is fine.
I was having problems with people giving me the entire backstory of the character and I had to fish though paragraphs of info just to figure out what they were supposed to look like. I respect your thoughts and understand where you're coming from~