I am absolutely the wrong person to evaluate this card on its playability. I am about as casual a player as it is possible to be; I still want to make a brain damage/click-denial HB deck with cards like Heinlein Grid and Kamali 1.0 and Mason Bellamy work. So when other people say that Whistleblower is generally not powerful enough to be playable right now, believe them. I'm not going to review this card on playability.
What I will review Whistleblower on, however, is its design, because I think Whistleblower opens design space in a way that gets missed when we only talk about whether or not it's worth a deck slot.
Whistleblower owes its lineage, of course, to Film Critic. Film Critic is a Runner tool for getting around nasty, hard-to-steal agendas like Obokata Protocol. It's also been Restricted since the beginning of the Banned/Restricted list, particularly because it's so damn good at what it does. At one influence and 1 to install, Film Critic is the gold standard tool for getting around defensive agendas. Want to have an easier time stealing Obokatas or Degree Mills? Slot Film Critic. Want to shut down SSL Endorsement? Slot Critic.
Film Critic, in other words, has the Jackson Howard problem: it's head and shoulders above anything else in its field. It's a first-order optimal card. While there may be niche cases when you pick something else before it (cases artificially made more common by Restricting the card), it's generally going to be an optimal pick. And that's boring and stifling from a design perspective.
Whistleblower is assuredly not a first-order optimal card. If more seasoned players are to be believed, it's actually pretty lousy. But weirdly, I find this encouraging. Jackson Howard, after all, wasn't supplanted by a single newly optimal card, because then everyone would have simply replaced Jackson Howard 1.0 with Jackson Howard 2.0. Instead, FFG recognized that Jackson's ability to sneak agendas out of Archives and back into R&D was critical enough to be available to all factions, and provided a number of powered-down options so players had choices based on the decks they were making. Attitude Adjustment, Gatekeeper, Genotyping, and Drudge Work all brought faction-specific Jackson effects on a variety of different card types. Preemptive Action and Distract the Masses were neutral options, both with their own costs or drawbacks. Breaking down Jackson's functions and divvying them up among multiple suboptimal cards opened up design space.
I think Whistleblower, underpowered though it may be, shows that NISEI recognizes that there's value in protection against defensive agendas and is interested in making that more accessible and varied. Maybe the next piece of protection against defensive agendas will come in the form of three faction-specific answers. Maybe it will be a neutral run event similar to Direct Access that ignores the abilities of any agendas accessed. Whatever it is, I have hope that future cards continue to explore this design space, so that the answer to defensive agendas becomes more interesting than "just slot Critic", and for that reason, I applaud the design behind Whistleblower.