Saddest thing about Ornn's items when he was released was it was just a stat buff and nothing even a little more interesting. Imagine if Zhonya's was 1 second longer, or recastable to stop the Stasis. Imagine if Warmog's passive also worked with mana. Etc.
We actually tested quite a few of enhanced effects in development. Turned out that it was EXTREMELY powerful and we decided that it would be too difficult to support longer term, so they became what they are today. Felt like a bit of a missed opportunity, but given the timing of everything I think it was the best decision.