Kommo-O's abilities are actually not that bad. Bulletproof makes it immune to bomb and ball moves. Its hidden ability Overcoat grants it immunity from weather effects (like Sandstorm or Hail) and prevents it being affected by powder moves (so it can't be put to sleep by Spore). But probably its best ability is Soundproof, which gives Kommo-O immunity to sound-based moves (like they ever so common Pixilate-boosted Hyper Voices used by Mega Gardevoir, Sylveon and Mega Altaria which would other OHKO Kommo-O in an instant).



I think the main reason Kommo-O started out weak was mainly because of its stat arrangement and lacking movepool. Whereas most of its fellow Pseudo legendaries have high offensive stats, Kommo-O actually has higher defensive stats. But it doesn't really have a solid defensive typing due to its x4 weakness to Fairies. What's more is that it has a lacking physical movepool (seriously, its strongest physical Fighting move option is Sky Uppercut) and has very little coverage. That's probably why Kommo-O started out weak.



But this new Z-Move really helps patch up Kommo-O's flaws. Boosts all of its stats to make it hit harder, faster, and tank hits better. Not to mention it hits both opponent's in a double battle. And hopefully when move tutors are introduced in Ultra Sun and Moon, they'll give Kommo-O some good tutor moves like Knock Off or Drain Punch to make a physical set more viable.