I think it's worth looking more closely at this.
"Normally, you can’t hide from someone if you’re in full view. A lightfoot halfling, though, can try to vanish behind a creature that is at least one size larger, and a wood elf can try to hide simply by being in heavy rain, mist, falling snow, foliage, or similar natural phenomena."
The most important thing here is: This implies that a halfling behind a creature that is at least one size larger, or a wood elf in natural phenomena, is in full view. Because if they weren't, that "normally, you can't hide... halfling, though" construction wouldn't make sense; there would be no distinction being made between the first claim and the second.
And yes, Hriston's view absolutely depends on not distinguishing between becoming and remaining hidden, but 5e seems to me to be quite clear about distinguishing between those.
FWIW, I took "staring directly at" to be intended as a stronger claim than "clearly seen", offered specifically to emphasize that it's not just applicable when you could be seen, but that it's applicable when you are being seen, and indeed, watched intently. You can still just go "poof" because that's the entire point of the power. Especially with the word "vanish" in use, because "vanishing" suggests a transition from seen-to-unseen, not just never being seen in the first place.
"Normally, you can’t hide from someone if you’re in full view. A lightfoot halfling, though, can try to vanish behind a creature that is at least one size larger, and a wood elf can try to hide simply by being in heavy rain, mist, falling snow, foliage, or similar natural phenomena."
The most important thing here is: This implies that a halfling behind a creature that is at least one size larger, or a wood elf in natural phenomena, is in full view. Because if they weren't, that "normally, you can't hide... halfling, though" construction wouldn't make sense; there would be no distinction being made between the first claim and the second.
And yes, Hriston's view absolutely depends on not distinguishing between becoming and remaining hidden, but 5e seems to me to be quite clear about distinguishing between those.
FWIW, I took "staring directly at" to be intended as a stronger claim than "clearly seen", offered specifically to emphasize that it's not just applicable when you could be seen, but that it's applicable when you are being seen, and indeed, watched intently. You can still just go "poof" because that's the entire point of the power. Especially with the word "vanish" in use, because "vanishing" suggests a transition from seen-to-unseen, not just never being seen in the first place.