[...]You could use Sparkling Crystal for easy 200 Damage plus the mill, but you can very easily make that 240 with Binding Mochi and Janine's Secret Technique and an attach. Against a Zard deck, 240 and losing 3 cards can be a big deal especially if it discards candies and rods.
Ogerpon with 3 energies Vs Hydreigon with Sparkling Crystal doesn't OHKO (but yeah it's still a problem)The biggest weakness I see with this Hydreigon ex is one Teal Mask Ogerpon ex will very easily demolish it the same way it can with Zard, and you can't really do much about it as a result. You would want to back up Hydreigon ex with Okidogi ex in case of an emergency.