Howl just needs a cast time and it would be fine IMO. Once we get the patch to better resist it (and cure it, I believe?) it'll be fine anyways, though. The point was that the cost of a great skill is requiring an item, like Wall of Thorns (I just wrote Thorn Trap again by accident. >_>) requires a Prickly Fruit.
Howling does have a cast time, with 110 base INT and 100 base DEX the cast is ~1-1.5 seconds. But thorntrap / Wall of Thorns aren't the skills we are really complaining about, they are made with the genetic special pharmacy so there are no failures ( you need 10 prickly fruits to make 2-4 thorny plant seeds ), the skills that people want items for mostly are "bomb", "acid terror" "acid bomb", and maybe "marine sphere". All of those skills can be used for leveling ( marine sphere is kinda crap though, hard to use properly and damage is crappy ) but require such ridiculous amounts of items to even TRY to make enough for leveling. They also have a high fail rate on non-dedicated pure brewers, and in the case of the "bomb" skill for bottle grenades it is TWO chances to fail making it.... chance to fail when making the alcohol and chance to fail making the grenade after you made the alcohol. This leaves alchy and bio players basically one crappy way to level until they reach genetic.... cart revo. If they have a pure brewer it is another story, but it is kind of stupid to be required to have 2 of the same class just to make items for the skills the class is supposed to be able to use. Especially when the class has no other decent skills until near endgame ( 100+ 3rd class, we used to have no decent leveling skill that DIDN'T cost our firstborn ).
Having a NPC sell the base stuff for our skills would be a good zeny sink. No one is asking for the NPCs to sell pre-made grenades and stuff, people are asking for NPCs to sell brewing consumables so they don't have to hunt for hours just to fail making 40%+ and wasting the materials they spent all that time hunting. At least with the failures of NPC bought materials that would take the zeny completely out of the market.