Originally Posted by Darjir
The reason why they have wriggles is that most regular neutral mobs have more armor than they do magic resistance, and major mobs (dragon/baron) actively debuff ad damage and/or attack speed. AP based champions usually have a faster clear time than AD based champions so are in less need of specialized gear to assist in jungling.
An item that either grants mana when killing neutral minions or grats extra protection from neutral minions would be far more useful. Freeing up the blue buff for your lanes or not taking huge damage early on would be far more useful to bring more ap champs in the jungle. Too easy to cripple them with a blue invade and any early counter jungle pressure will usually find them at lower health than AD champs and an easier kill.
Close but not quite. The real reasons are:
1. Ad champions are more item-dependent than non-ad champions. This affects jungling in particular, because all of the non-ad champions that are capable of jungling can do so with minimal items. Madred's Razor was required on many ad champions to jungle for the longest time, and I am getting to why the addition of Wriggle's was eventually needed considering that Madred's already filled that role.
2. Everyone must ward including the Jungler. Gp10 items are the real "warding items", but ad-junglers in particular could not really use them because GP10 items are designed to be weak for their cost. The investment is meant to include trade-offs, and item-dependent ad-junglers simply could not afford that weakness while jungling. Avarice Blade in particular is one of the worst items that a jungler could pick up, because the damage boost from crit chance is too inconsistent.
3. Adding a strong ad gp10 item would make gold-generation far too easy for ranged ad carries. An item needed to be devised that would help ad junglers afford wards without cutting too much into their more limited gold, and without giving ranged ad carries too much of an advantage in lane.
Wriggle's Lantern is not perfect, but it gets the job done with minimal problems compared to alternatives. Ap and tank junglers have absolutely no problems using HoG, Philostone, or Kage's Lucky Pick to help buy wards while jungling, so no "Wriggle's item" is needed.
On the topic of a "support wriggles":
1. A warding item for supports in lane would further be redundant considering gp10 items are the warding items and do buy "free wards". One ward every 3 minutes with 15 extra gold leftover.
2. This game is designed with trade offs and a cap to power. Riot considered adding a ward slot, but decided against it under the consideration that filling that last slot or buying more wards should be a conscious decision. Leaving that slot open for wards on one champion on each team is actually worth doing in the end-game because vision and positioning are just so important, but it is understandable why players hate being forced to make that decision.
3. Based on Xypherous's words on this issue, the most that supports can hope for is an eventual item with some kind of reveal effect. Such an item may conceivably be added at a later time, and if it is implemented it would probably work like a low range clairvoyance.