What are your thoughts on CDR Tank Zilean?

Most notably in the top lane. Given I am only mid-silver, but I tried it out a few games and had some pretty okay success.

The build I tried out was:

CDR Boots Frozen Heart Seraph's Embrace (Or RoA) Iceborn Gauntlet Locket of the Iron Solari Banshees/GA/Randuins/Whatever

The damage output is still pretty high, but you can spam all day with the new mana costs and the utility with your low CD ulti and E are amazing. And on top of it all you are durable.

Thoughts?