AP junglers have an advantage on AD junglers. They have a much higher jungle speed than most ADs. Even the ones who can keep up the pace initially like Shyvana still need to build more defense initially because of something else lacking (like innate sustain).

AP junglers either have enough AoE damage that they don't have to worry about minions hitting them after level 2 or 3, or they have innate sustain beyond the level of any AD champion's dreams.
And yet I see Kage's used far more often than Avarice. There are maybe two champions I have seen use Avarice Blade consistently (Gangplank and Tryndamere), and they've pretty much dropped off the face of the earth in terms of viability. Occasionally when I wanted Ghostblade, I'd put it in my Wukong build because of how insane his ulti damage is when his target has close to no Armor.

You literally never see Avarice blade on junglers or ranged AD champions because of how inferior it and Ghostblade are outside of melee solo top champions, who can afford to not buy Madreds because the minions are fighting each other, not focusing them.

i definitely like the idea of having an ap item with a ward active. But i don't think that it should have the % chance to do extra damage to a minion like wriggles does because name an ap junlger that needs that? there isn't one. but a simple item like:

40 ap
30 armor
10 spell vamp
ward active

I think this would be pretty cool. but then again, it'd have to cost a little bit more gold than just what the stats give because it has that ward active. that active isn't free.

also because it gives armor and no magic resist it wouldn't really be viable for ap carries who go mid to get it because they're going against another ap so if anything they need magic resist and not armor. this would be for ap bruisers and ap junglers

Just to simplify things for you:
-Ap champions and real tanks are mostly LEVEL-DEPENDENT. That means that most of their damage comes from abilities as they level, and the items they actually build are not that important to their jungling. This allows ap and tank junglers to jungle with Philostone and/or HoG and/or Kage's Lucky Pick....Every ap or tank who jungles can use at least one of those items while jungling.
-Ad junglers are mostly ITEM-DEPENDENT. That means that most of their damage comes from items, and their jungling capacity is more directly tied to what items they build. Back when the jungle was difficult, most ad-based junglers could not jungle without Madred's Razor......It was actually impossible for them to survive and build up items fast enough.

The item-dependency difference is important because junglers need wards, jungle-gold is more limited than lane-gold, and ad-junglers cannot afford to gimp themselves with gp10 items that are balanced around providing a much lower value in stats than their gold costs.

Gp10 items are the real warding items in this game, providing gold for 1 ward every 3 minutes with 15 extra spending gold--it was exactly 1 ward every 3 minutes back when Wards costed 90 gold--however, ad-junglers could not use gp10 items well enough to jungle; therefore, they needed another alternative. No balance gp10 item would work, so Wriggle's Lantern was developed.

The conditions that made Wriggle's Lantern's design necessary do not hold for any non-ad champion archetype. This is why all talk of an ap, support, or tank wriggle's is fundamentally flawed, and there should not be an equivalent.