Hatred Hatred requires an unblocked creatures and a higher life total than the person youre attempting to take out of the game
Whether or not Venerated Rotpriest ends up a four-of in Infect reminds to be seen - usually Im the guy dying to Infect, rather than killing opponents with poison counters, so I'm not an Infect expert by any means, but at a minimum the new one-drop offers enough upside and unique lines that Infect players will try it, and I wouldnt be surprised to see some number of Venerated Rotpriests stick in the deck
Sword of Vengeance (trample) and Basilisk Collar (deathtouch) equipped on to Ink-Eyes, Servant of Oni can help that strategy
The same doesn't happen with Ninjutsu
Cards that give you extra benefits for milling out your opponents, like Syr Konrad the Grim and Blackbloom Rogue
Value when it comes down, then more value if it goes unanswered