What if we could load only the abilities that we want for Cancan? (This is a rough sketch of the concept.)

filtered_ability.rb

class FilteredAbility
  def initialize(user)
    @user = user
  end
  
  def ability_for(obj)
    class_abilities = organized_abilities[obj.class]
    considers = class_abilities.keys.select{|a| @user.send(a)}
    considers.each{|c| create_ability(class_abilities[c])
  end
    
  def create_ability(ability, obj)
    send ability.key, obj.class, ability.value # this isn't it precisely, but something along these lines
  end
  
  def organized_abilities
    {
      # Class: {
      #   :boolean_user_method => {
      #     can: {
      #       [:read, :list] => condition_with_way_to_inject_dependency_on_obj
      #     },
      #     cannot: {
      #     }
      #   }
      # }        
    }
  end
end