Having seen plenty of businesses throughout my life, both successful ones and less successful ones I'd say the most important traits are:
- the ability to execute
- having drive, focus and flexibility to adapt
- being able to manage a team and keep it focused, motivated and on track
this is valid for both the technical founder and the business founder alike.
In a perfect team the business founder has a very good understanding of the tech side and the technical founder a good understanding of the business and marketing side. Product is nothing without sales and sales nothing without product. Despite this being obvious I have seen several companies fail on this.
Last not least it depends on the product. The more complex the tech is the higher the share of the technical partner should be and vice versa the more specialist business domain knowledge is needed, the higher the business partner's shares are.
I was one of the "business guys" at DigitalOcean from very tiny to big. Execution looked like: 20% of the time in meetings discussing what the next period of time without seeing each other was going to look like and 80% of the time on flights and in hotels. My mantra was always "be directionally correct, go to market as hard as I can every single day, and fully trust the engineers building the products around me".
If your "business cofounders" aren't closing deals and landing sales they're useless. So if you're going to join a "non-technical founder" they must both have the contacts or a in in the industry you'll be trying to join and must be a great salesman.
If they don't have that, walk away, this person has no value.
The ability to execute means to deliver timely and on budget.
I have seen people who would not be able to set up and manage a hot dog stand and yet they were trying to run a business with 50 employees. The only result was burning money like there was no tomorrow.
In a perfect team the business founder has a very good understanding of the tech side and the technical founder a good understanding of the business and marketing side. Product is nothing without sales and sales nothing without product. Despite this being obvious I have seen several companies fail on this.
Last not least it depends on the product. The more complex the tech is the higher the share of the technical partner should be and vice versa the more specialist business domain knowledge is needed, the higher the business partner's shares are.