As a long time Sunny player, I am incredibly excited she is getting more support. And in this pack, the card she gets is a weird one.
After spending 2 clicks and winning a trace, you get to take a peak at the corp's entire hand. That is great on itself, as knowledge is power. But not only that, you get to send 2 cards back to R&D. In a way this card works somewhat similarly to Utopia Shard, disrupting the corp's hand and throwing a wrench into any plan they might have had. Brutal, especially against combo decks relying on Hard-Hitting News. Biotic Labor, etc.
The downside is though, while Utopia Shard could potentially hit agendas, which you then could go grab from a potentially ill-defended archives, White Hat requires you to run a now slimmer HQ again. If you can follow it up with a Legwork that is definitely a powerful play, albeit slightly situational.
Also, don't even think of playing this card outside of Sunny, with its dependence on high link AND 5 influence cost to boot. This is definitely mummy's party.
Is White hat good? For sure. Good enough to see a ton of play? Eehhhhh, we'll see. I don't think it will turn Sunny tier 1 overnight.
Now Black Hat on the other hand though...