Most desired secondary skills for an Indie Game designer

If you’re an artist, composer, or programmer in an indie environment, what are some skills you wish your game designers had or had more of? Like if you were a 3d artist also responsible for rigging bipeds, would it help if your game designer was, say, familiar with making sophisticated MEL/Python scripts for rigging not currently on the market, or for this niche area of rigging you dislike doing or something?

Or if you were a composer, would it help if your game designer was able to communicate to you in formal musical notation instead of writing out shoddy tabs or humming a motif to you?

Answers can be very specific like mentioned above, or general as in “game designers would communicate this or that aspect better”.

What did you wish your game designers were able to do other than defining/designing mechanics and user systems?

Write code.

Game designers who can’t demonstrate their ideas are worth considerably less than those that can. Personally I wouldn’t hire designers with no programming or scripting ability, because it means I need two people to a job that one person should be able to.