Titanic would be a much better item for it's intended users if the passive had a CD

And did more damage. Something like one proc every two seconds. Maybe keep the cone damage on each hit and only have bonus damage to the primary target every few hits.

The champions who Titanic Hydra is designed for aren't the kind of champion who builds a bunch of AS, they're the kind of champion who wants to pull off a spell rotation and throw a few autos in the mix. The champions who are abusing it are ones who can break the on-hit portion. Giving it more passive damage on an internal cooldown makes it much worse on the champions who abuse it, while keeping it roughly the same or actually improving it on champs like or , since they tend not to build any AS items.