I feel like this would fit the bell curve meme -
Novice dev writes simple code
Intermediate dev writes complex code
Expert dev writes simple code
Novice dev writes simple code
Intermediate dev writes complex code
Expert dev writes simple code
Something along the lines of "Hey, you're a great developer, really smart, you really know your stuff. But you have to stop reaching for the most complicated answer to everything"
He took it to heart and got promoted at the start of this year. Was nice to see. :)