First off, I am silver, I am bad, blah blah. This is my opinion and should not be considered objective facts.
I have played against Ornn a few times now and I find him too forgiving. Several times do I think I dodge his last W tick or his first part of ult, but no, I get hit anyways, leaving his Brittle effect on me for a lot of damage. The abilities seem to just have a too wide hitbox.
Add to that, I have dodged his full combo a few times, going ham on him afterwards, resulting in me being close to him. That resulted in him not dying and him having enough time for his CDs to fall off and him killing me from his second combo. From this I think he is too tanky for the damage he does and too forgiving if he does not land his stuff
What are your opinions and observations of Ornn so far?