Can a competency model be too detailed?

Of course. It's easy to get too detailed in a competency model. If you look at a list of soft skills, I’m sure they would apply to almost every job (written communication, problem solving, teamwork, etc.).

Focus on “critical to success”

A competency model is what best defines success in this role. That’s why with a standard competency model, you might start with 40 or 50 skills and you select 20 that are appropriate for this role in your organization.

Remember that the competency model needs to be actionable. If you have 50 skills in a model and I have 10 skill gaps, where do I focus? Narrowing to those tasks/skills that are most critical to success ensures that you can help people focus on where it will make the biggest impact on the organization’s strategy and objectives.

How many skills in my capability framework is too many?

30 is generally too many, but it depends on the role. For a salesperson or people manager, you may not want to go above 20-25.