Ori's biggest issue is identical to how Lux was

She's too safe. Period. She has no danger to her.

While her Q range is all right, her ball stay range is really high, allowing her to harass from afar with her W which does an asinine amount of damage for what it offers. Her shield is spammable thanks to the absurd availability of CDR in her core items and shields for the equivalent of a Janna shield. While theoretically Janna's would scale better into late-game, mid-lane Janna isn't exactly viable and support items don't offer quite so meaty AP. Meanwhile, Ori will be building straight AP, so astronomical odds are, Ori's shield won't fall too far behind Janna's.

Ori also has a combination of defensive and offensive utility on her W with both the speed up and slow, making her incredibly difficult to keep locked down and for enemies to jump her effectively. To make matters worse on top of all of this, Ori also has some of the best AoE damage with high scaling in the game right now, so not only does she do a lot of things that other champs specialize in better than them, she also is just straight up better at mage-ing than other champs right now.