pg 55
Accessories: These keywords identify items used with the power. If you have a proficiency bonus to attack rolls and damage rolls from your weapon or an enhancement bonus to your attack rolls and damage rolls from a magic weapon or an implement, you add that bonus when you use a power that has the associated keyword.
A wizard of the spiral tower's sword, a pact blade, and a holy avenger, are all implements when used to cast a spell/prayer with the implement keyword. The only bonus an implement adds are enhancement bonuses to attack and damage rolls, not proficiency bonuses. The REASON they don't get proficiency bonuses? Because they are not weapons when used in this fashion. Likewise, any other bonus one would have when using the weapon as an implement do not function unless the bonus also works for implements, which only enhancement comes to mind. An attack with a longsword as an implement is not an attack with a longsword as a weapon, but with an orb/staff/wand. A pact blade is a "warlock implement" not a light blade when used to cast spells, and a holy avenger is a holy symbol. Weapon feats do not apply, nor do weapon PP abilities, class abilities, or anything else of the same vein.
Staffs, also, do not add a proficiency bonus or any weapon feat bonuses to damage or hit when used as implements, because a staff is an implement that can be used as a weapon, not both at the same time. As an implement, it qualifies for no weapon bonuses. It is a special rule that lets it inherit any enhancement bonuses when used as a weapon, not something innate. If you hit someone with an orb or stab them with a wand, you do not get enhancement bonuses, these are just regular improvised attacks.
Am I the only person in the world that finds all this to be obvious and to make sense?