Is there anyway to get the $form_state inside a hook_block_configure? Is there any way to get the $form_state inside a hook_block_configure()? I'm trying to do that to make #ajax work on hook_block_configure().
You don't have this information, but you can access to it with hook_form_alter. But to access to this form (that call block_configure) you have two form_id block_admin_configure and block_add_block_form.