This is a review of the expert side of the card. I don't really play standard and one of my main concerns lies in the fact that it also affects minions.
This card is just obnoxious.
Status effects are really strong if not borderline op(at least on solo), so having a few ways to give status-based decks a harder time seems like a great idea; however, this isn't it. Formidable Foe fails to properly address what it's trying to counter, and it actually unevenly destroys cards that are hardly the worst offenders of the status abuse meta.
Take Spider-Girl, for example, she's a strong tempo ally that gives us a bit of a break if we are swarmed by minions and can't take them all out or if we are engaged by a bigger one that we can't really kill in one turn. Now she's borderline a vanilla beater since minions shouldn't be left alive long enough for them to be targeted by two of the same status effect(especially in Aggression!), nor does it seems like a good resource investment.
Mockingbird is another cool ally that got the short end of the stick. While, at first, she might seem like one of those main culprits for the existence of Formidable Foe, however, in reality, one of her biggest selling points was giving access to Stun for decks that otherwise wouldn't have access to it and be an effective defensive choice.
Many heroes have a random status card in their signature slots, like Speed Cyclone from Quicksilver, or Widow's Bite from Black Widow. These Heroes might not invest in these types of effects(or might be playing an aspect without any), which again, completely negates their use.
The worst part about Formidable Foe, however, is yet to be mentioned: It's always there if you choose to play standard/expert set 2. It cannot be avoided, nor countered, we can either pay the toll or completely avoid the set (there's also house rules, but it defeats the purpose). This design makes an already frustrating set(this is a rant for another day), even more, frustrating to play against, and forces players to either meta-game accordingly(which is dumb for a set that can go into every encounter), be stuck with duds in their deck, or not play with the new set.
In the end, this feels like a solution as elegant as burning down your house to deal with your ant problem. It seems like this effect would have been great on a side scheme, add 3 copies into the standard set with a "add this card to the field" boost effect and call it a day(maybe add another type of Status hate into the expert set), but we really needed all those "card X but give it Surge" that we got instead, right?