Would like to throw in some more 

1. Ability to consistently find "critical" problems 

 How?

 Through 'Understanding' of the usage,impact and risk — on the product,business,customer,project 
And a confidence to advocate his work(e.g. bugs raised).

2. Positive Leadership traits are a must in my book 
    - Ability to handle problems single handedly
    - Inclination (atleast) to take up complex and hard tasks 
    - Ability to mentor peers irrespective of his job title 

3. Great at relationships 

    - Someone who is good at developing and maintaining positive working relationships with Developers, Project owners and within the test team