I didn't think of it that way. That's interesting to point out @Hanuku; thanks for that.
Additionally, from the articles regarding this Senator's bill, there are loopholes as to how he defines "Pay-2-Win" because microtransactions doesn't automatically mean they're P2W. Some people spend microtransactions on costumes, cosmetics, cool in-game aesthetic effects, basically anything that gives neither an advantage nor disadvantage, which isn't explicitly defined in what the bill entails.
I agree. Making it where loot boxes give items that are all satisfactory to a player in some way, without the out-of-luck cards as you described, would certainly make these boxes avoid falling under what the bill declares "unfair gambling" such that they aren't unfair. However, keep in mind that any item that makes a player stronger, that can be bought with cash, is P2W; that can't be dismissed, and boxes like the [Lustrous Box] provide contents that are P2W, which is what this bill is trying to make illegal in the U.S.
Interesting analogy you bring up as it relates to law, but law and in-game P2W are two different concepts.
I agree, the small defense NCSOFT adds to Blade & Soul is that their events, with the loot boxes and such (Trove, Lustrous, etc.) have a small portion that can be obtained for free. However, the free might not be enough in the eyes of many F2P players, in which this defense is denied by a majority of them.
It's a difficult balancing act trying to seal the gap between the "whales" and the F2P players because once a player is able to buy materials for upgrading their character, that's when the gap opens and becomes very hard to close.
If anything, NCSOFT should look into making things fairer for F2P players. I can't stress enough how important that will be for the lifespan of this game. Then again, they're greedy... might expect the worst to come.