Each instance of extort triggers independently, so you can pay two for two drains for each spell cast
There's basically no good outcome for your opponent when this thing hits the table
The Idea About a year ago, memelord and know degenerate Magic AIDS posted this video: With this video, Modern Hardened Scales decks were born
is a daunting mana cost that basically restricts this blue creature to mono-blue or 2-color decks, but recasting your best instants and sorceries extends the lead cards like Time Warp and Breach the Multiverse naturally provide
Outside of that general benefit, we do have a few payoffs and upsides
We can't identify a ton of new cards that would make Rot Hulk loads better than it was before (though Geralf the Fleshwright seems like a fun one from MTG Thunder Junction), so it's likely the overall popularity of Wilhelt is increasing, rather than the proportion of new Wilhelt decks containing Rot Hulk going up