Sure you lose out on tough no knockdown exemplar, but everything's tough as a rock here by default. The initiates and the champ are great with +2 arm for ramming them into some unit and jamming. And hand of vengeance (on FoS to boot), coupled with a feat turn will allow your jacks to clear up the mess (I'm guessing a counter-charging and then vengeance move FoS is pretty unpredictable). Hand of Silence is actually a good surprise torpedo to launch on feat turn.
Basically rely on Champs, Initiates and Idrians to engage, then the rest of the list rely on feat turn to smash face. Oh, and Kreoss2 likes a wall to stand behind while he castigates. This is his true calling before the exemplars stole him.
My concern would be if you're generating enough volume of attacks outside of feat turn. But it would be hilarious to see auto-hitting, impacting Champions.
Yes, it's very feat oriented. But I've personally always felt that Kreoss2 is all about the feat (and castigate, if against hordes) and so many things counter tough that I'm not sure his tough bubble is worth it. The new sacrosanct is nice against things like legion and circle heavy infantry/cavalry with multiple attacks. Also hand of vengeance in FM makes countercharging jacks all the more dangerous.
I've considered dropping Hand of Silence and adding a sunburst+hierophant instead (the points work out) since the list may not have enough bodies to support both sanctifier and hand of silence.