Remove 'Pages' gridfield, scaffolding is making it available when it shouldn't be
Make extension move 'Children' gridfield to 'Root.Main' (less clicks, immediate clear that taxonomy terms have children to new users)
Rename 'TaxonomyTermExtension' to 'BasisTaxonomyTermExtension' as the first name you go to choose when extending TaxonomyTerm is TaxonomyTermExtension (so this frees that name up)