At the time of posting the patch that will give Zai Chi Overwhelm is not live yet so this deck list hasn't been fully tested. However I think dropping free Zai's, Kerasaurs and Cirsos may well have a place on ladder. Especially considering Overwhelm Rod was already good enough for top 200.
However this is not an experimental build and I wouldn't recommend it for ladder. Grimfan was running a Praxis Overwhelm build a week ago that looked like this,
https://eternalwarcry.com/decks/details/kAjr1FwQZ7E/grimfans-overwhelm-rod
that you could use for ladder if you wanted to climb with an Overwhelm Rod deck (I ran it from 250 to 150 last week and it should still be good for Masters at least).
Personally I am mostly using variations of FTP decks since the patch buffing Zai.
Or Cult Aspirant insted of Champion of Fury, does well with Shepherd's Horn