How to override core taxonomy/term/% with a view? I have enabled the taxonomy/term/% view provided by the Views module but taxonomy term views are still handled by the core. Modifications has no effects and hooks such as  hook_views_pre_render() are not invoked.

However, views explicitly specifying a term such as taxonomy/term/5 work. 

Do you have any idea on how I can override the core default taxonomy?
The Taxonomy views integrator module can help you; it allows selective overriding of taxonomy terms and/or vocabulary with the view of your choice.