What is Ornn supposed to do exactly?
[ ] Reliable CC [ ] Tankyness [ ] Damage [ ] Jungle clear speed. [x] Gives marginally better items at an arguable gold efficiency cost.
His Q is incredibly easy to dodge, with only a couple of steps (ie, right clicking once) needed to dodge the follow up E knockup. His E is his only form of cc outside of his ult, but only if he hits terrain. Like a crappier poppy E. Crappier because it's far less reliable. But hey, it cant hit multiple people if they have the brainpower of a half eaten dorito and clump against a wall. His W does decent damage and helps with clear, but its range is abysmal given that it also slows him. Slows him. Did you actually manage to land a Q E combo? Great, now slow yourself to guarantee they get away. And whose idea was his ult?
"Hey, I've got an idea. Lets give him a skillshot, that does marginal damage with no cc, but wait, you then have to fire a second skillshot with precise timing to hit your first skillshot in order to trigger a THIRD skillshot, at which you will then be able to knock them up, if you managed to use all three skillshots perfectly. And even then it'll probably do freaking nothing I don't know".
And tankiness? Did anyone think the crappy shield on his W made up for his atrocious base defensive stats? A conditional shield that like the rest of his kit, is slow, awkward, and easy to dodge? Leaving any champion with even a mediocre move speed buff or simply a faster base movespeed completely free to easily dodge the skillshots and kite him until the heat death of the universe.
And the item upgrades? Some are decent, but you are still investing a solid chunk of gold that could be going to another item entirely. Sure, at the end of a 45 minute game those items are going to edge out with both teams at full builds. But in the average game? It doesn't feel worthwhile half the time to invest in the better item. Why get the upgraded sunfire cape when you should be investing in an MR item? Why get the upgraded Infinity edge when you could be building an essence reaver or statikk shiv? Sure, Ornn can dominate a top lane matchup with the item forging. Investing in a couple of early game items without backing in order to negate a bad lane matchup and pressure turrets, but aside from that, Ornn is bad at pretty much everything. Not enough reliable CC or strong enough stats to support. Not enough reliable CC and too slow with not enough damage to jungle. Melee and immobile so no weird mid or adc builds. There is nothing he really brings to the table for either solo que or competitive play.
So, how can we fix him? His E should be able to knockup opponents without hitting terrain. Perhaps bonus percent health damage if he manages to connect with terrain instead. You shouldn't be able to miss the redirection on his ult, and the initial shot should have a stronger slow. Give him a bit more early game tankiness, and I think you might have an actual viable pick.