Due to his Mad Enhancement buff, the longer he remains on the field and fights, the stronger he gets, so your opponent may want to remove him quickly with effects
While Landorus is a deck that aggressively uses gust cards to steal easy KOs in other formats, it is perfectly content using Hammerhead to set up damage on multiple Pokmon and clean up damaged targets on the Bench in NXD-XY
The ability to copy loyalty abilities can be lethal when you sequence things properly
Take my aggressive Nahiri, Forged in Fury deck that wants to curve out it doesnt run any lands that come in tapped, other than an Inspiring Vantage, and three MDFC lands
Graven Cairns, for instance, was just re-released in Duskmourn, while Flooded Grove has been printed into the ground, with recent appearances in Thunder Junction, Bloomburrow, Duskmourn, and Tarkir: Dragonstorm
While an obvious way to break this commander may emerge once its been out for a few weeks, I think its more fun to just take sagas that you personally want to play with and find a way to see how they all work together