... Actually, referring to the post below, what Allen is advocating (with qualifications of course) is first person singular as a kind of "default person", which I'd say it already is in contemporary poetry, and indeed, in lyric poetry of all the ages.
But, to explore you a little more…
In English there are many senses of you.
You can be plural you (speaking to two or more people at once) or singular you (speaking to one person); it can also be general (sometimes called indefinite) you, which is like "one", as in informal speech when we give instructions ( "to repair a flat bicycle tire you have to first determine where the leak is"), or a specific (sometimes called definite) you, as in "I want to speak to you."
What Allen is complaining about is an over-indulgence of the indefinite you, which can get more than a tad presumptuous if carried too far.
But here's an amazing poem written in the indefinite second person, that doesn't just "work" but blows me away -- because it is so vividly rendered, because it takes you into such surprising spaces.
WHERE YOU GO WHEN SHE SLEEPS by TR Hummer
What is it when a woman sleeps, her head bright
In your lap, in your hands, her breath easy now as though it had never been
Anything else, and you know she is dreaming, her eyelids
Jerk, but she is not troubled, it is a dream
That does not include you, but you are not troubled either,
It is too good to hold her while she sleeps, her hair falling
Richly on your hands, shining like metal, a color
That when you think of it you cannot name, as though it has just
Come into existence, dragging you into the world in the wake
Of its creation, out of whatever vacuum you were in before,
And you are like the boy you heard of once who fell
At the top swirling in a gold whirlpool, a bright eddy of grain, the boy
You imagine, leaning over the edge to see it, the noon sun breaking
Into the center of the circle he watches, hot on his back, burning
And he forgets his father’s warning, stands on the edge, looks down,
The grain spinning, dizzy, and when he falls his arms go out, too thin
For wings, and he hears his father’s cry somewhere, but is gone
Already, down in a gold sea, spun deep in the heart of the silo,
And when they find him, his mouth, his throat, his lungs
Full of the gold that took him, he lies still, not seeing the world
Through his body but through the deep rush of grain
Where he has gone and can never come back, though they drag him
Out, his father’s tears bright on both their faces, the farmhands
Standing by blank and amazed—you touch that unnamable
Color in her hair and you are gone into what is not fear or joy
But a whirling of sunlight and water and air full of shining dust
That takes you, a dream that is not of you but will let you
Into itself if you love enough, and will not, will never let you go.
For most of us, this you becomes a kind of I in a dream, an essential or existential I.
At least part of the effectiveness of you here, though, is that the narrator doesn't stay in that difficult-to-sustain voice very long: the poem soon becomes a third person narration with the description of the boy's experience of falling into the silo, and we only return to the you in the final lines. (That the boy's subjective experience of his own death can only be imagined -- that it is indeed the "stuff that dreams are made on" -- of course contributes to the dream-like quality of this poem.)
However Hummer brings it off, that attainment of a dream-like quality is, I would say, is the challenge of writing a poem in the general or indefinite you.
I have also, by the way, seen you begin as a kind of general you, and then turn quite accusatory as that you takes on the particularities of a specific you. That, too, can be quite compelling.
As a side note, in languages like Spanish, French and others, the English second person may be parsed into different pronouns which inherently specify whether one speaking hypothetically, to one person or to two or more. But in English, well, we do have this ambiguous or multi-purpose you which requires context to clarify. The effectiveness of the unclarified you depends upon the persuasiveness of that context, and ultimately, how you is used.