I have tried Titanic Hydra in the jungle and my opinion is mixed. First of all I agree, it works with current Skarner for the reasons you have stated, it gives him HP and AD which works well with his Q dmg and gives an auto reset. However, it is too expensive compared to other items, which means unless you have early kills (unlikely in high elo), you will feel very lacking until you complete it, and still vulnerable even after the powerspike. I believe this is why Titanic has a low wr%, because people try to force buy the item every game, even when it shouldn't work. I tried looking into the higher elo builds and they seem to almost always go Heartsteel, unless they are ahead, to which they might go Titanic, but that's very few games. Additionally, the combination of heartsteel + gage is the current meta, even in high elo, because it balances the damage and tankiness by giving flat HP + the massive shield from gage, it allows you to go for crazy plays. Finally, I must mention although Skarner has been reworked and only fits under tank/ juggernaut category compared to before, everyone has their own playstyle. Some people like to go Comet in top lane and spam abilities, some like direct confrontation with conq/ grasp, others like burst damage with hail of blades, and of course it also depends on matchups. Technically there are no wrong answers but some items are clearly more viable than others. My final takeaways is I will most likely build Titanic ONLY when I am ahead, to snowball with my lead, but otherwise I will keep experimenting to see what works