I think rhythm and flow are certainly more important than rhyme in spoken word. However, I think one of the best reasons for a poem to rhyme is the fact that different people will read the same poem VERY differently, even reading around punctuation in different fashions. Rhyme gives an element of cohesion, so that everybody who reads it is getting the same thing. I think poetry is as much about combining sounds, making internal rhymes, plays on words, cool combinations of odd syllables, mish mashing and creating new words as it is anything else.
For example, my favorite poem is John Masefield's "Sea Fever"
I must go down to the seas again, to the lonely sea and the sky,
And all I ask is a tall ship and a star to steer her by,
And the wheel's kick and the wind's song and the white sail's shaking,
And a grey mist on the sea's face, and a grey dawn breaking.
I must go down to the seas again, for the call of the running tide
Is a wild call and a clear call that may not be denied;
And all I ask is a windy day with the white clouds flying,
And the flung spray and the blown spume, and the sea-gulls crying.
I must go down to the seas again, to the vagrant gypsy life,
To the gull's way and the whale's way where the wind's like a whetted knife;
And all I ask is a merry yarn from a laughing fellow-rover
And quiet sleep and a sweet dream when the long trick's over.
I encountered a nice Irish girl in my travels who also held this as her favorite. But we both read it with different rhythms, stresses, and pronunciation. But, the rhymes at the end of the lines (hey, that was almost a rhyme, bit of a stretch, but still! :D) held it together, even if we pronounced flying and crying different, because it served as marking posts to work things around.
So in short I agree, rhyme is not important, I seem to recall some introduction to Paradise Lost consisting of John Milton stating that "poetry has no true need of rhyme nor meter". Thought I think it takes a serious talent to write a pleasing poem that does not have a consistent rhyme or meter structor of some sort. But STRUCTURE, is the key, of some sort. Look at Chiasmus and other ancient poetry forms.
This was a largely uneccsary post. This poem was better in structure but I think I wrote like the same thing in high school.
Epstein didn't kill himself.