Although a tricky question for one primarily self-identifying as an ancient historian or historian of religion at best, my impression of what should qualify a biblical scholar or theologian as good should be what is applicable to what in general makes one a good scholar of humanities.
It comprises yet transcends the study of source-texts and knowledge of languages ancient and modern. Obviously Quellenforschung remains core, yet a good scholar should be open-minded towards other disciplines, willing to see the wider picture of contexts of a text or person studied, thereby critically assessing one’s own discipline.
Creativity, curiosity, and a critical eye are key. Appreciate academic freedom, use it, and be not paralysed by dogma.
Jessica van ‘t Westeinde, Postdoctoral Researcher, Universität Bern