I think the most important skill to expect of a non-programmer is presentation.

Startup success boils down to two problems:

1. Building the product

2. Finding customers

Be it personal powerpoint presentations, meetings, preparation of advertorial material, giving talks, or website content, the presentation of your product is really important. It is what differentiates a company solving real problems from a bunch of geeks doing some geeky stuff in a lab. It reveals the potential of your solution to real users.