Poetry without strict meter or rhyme is hardly formless if it is done well since I think the aesthetic of the early modernists, from Whitman through Eliot, Pound WC Williams and up through the present day was to model cadences on the inflections of real speech. Idealized speech, of course, but speech all the same as the inspiration for jettisoning the mathematical formulations that dominated serious poetry.
There is something in the best of lines of non-rhyming, unmetered poems that gets at a number of verbal nuances that might otherwise not be available to a poet concerned with adhering to a conventional approach. As with metered verse, we have concern ourselves over which poets have an ear, a musical sensibility that can select the right words for a difficult perception to get across, and who knows when to pause, to construct a high, frantic rhetoric, when to calm down, when to stop talking. Robert Creeley, John Ashbery, Frank O'Hara, Thomas Lux, masters of free verse, geniuses even, are every bit important to the history and extension of poetry and poetic gesture as were the usual suspects lurking in the ranks of the older dead white males.
We do have blather, of course we do, we have pompous and amorphous spewing of pretentious, slender lined tripe that is hideously dreadful, but this, I think, is the case for poetry in general, regardless of era, style, aesthetic, politics; most poets are awful and what they write deserves a can of gasoline and a match. The point of it all, among other points to consider and define, is discussing what makes for a good unrhymed poem. I would present Creeley and Thomas Lux as examples, and I would go as far to maintain that John Ashbery, Ron Silliman, and Ishmael Reed are no less perfect examples, though of a more expansive, abstract leaning. It's a big subject within a bigger tent.
Entertainment has virtues and cannot be discounted altogether; we seek to have our senses engaged in some worthwhile way. Art, among many others near intangible things it gives human beings, brings us pleasure and is often times sensual in- itself, plain and simple. I do have a love of clear, vivid poems with sharp, precise imagery, but there is quite a lot of pleasure I get from reading poets who are less conspicuous in what they're doing. I like Eliot, Stevens, Dickinson, Silliman, Perelman, Armantrout, Oppen, Bishop. Not everything that is difficult is diffuse, though much of what attempts a more abstract language is merely diffuse and deadening pretentiousness. Like everything, there are those excel in particular styles, and there are the majorities who are merely rattling their keyboards against their belated desires of anthologized glory.
There is no reason why entertainment cannot be the height of art, truthfully. Some of this depends on what entertains you; criticism, in a sense, is the attempt to determine the art within entertaining items and to define or defame those terms as best as we possibly can. It is very subjective and can lead us into blind alleys where vague absolutes irresolutely bark at one another from their respective tethers. Critics and philosophers have debated the utility of art since The Republic and before, and aside from some inspired manifestos about how the surest art will revolutionize and utterly transform the human experience with the material and spiritual realms, the general consensus, so far as my academic and independent readings, is that art's basic function is to create joy, i.e., pleasure, entertainment by any other term. In those terms, art is hedonistic by default, created and sought out because it pleases the creator and the observer. What moral/philosophical/sociological/political insight or "lessons" the art conveys or that one discerns is merely incidental. Aesthetics, of course, is not a philosophy, but merely a kind of inquiry--it is a practice that can be attached to virtually any moral or philosophical undertaking. Hedonism, though, is not a philosophy at all, and I don't recall reading any serious defense or affirmative presentation of the "do your own thing' approach in over four decades.
I like ugly, imperfect, ambiguous art, especially poems, but I also love form, elegance, an ordered pairing of opposing things that once, brought together, gives us a sublime thing indeed. The problem with insisting that a poem should be "beautiful" according to a standard imposes limits on what the poet can do with a work and, in effect, implicitly dictates that a work adhere to requirements that are ill-suited for an emotion, an idea, an event, an experience that would motivate a writer to compose some lines. What gets to me is a poetry that gets across what the poet attempts with a mastery of techniques that are true to themselves, not an ideology. The elements that seem to break away from the phrase making one expects and combine with a writer's honed instincts for developing a rhetoric that allows a poem to stop you for a moment, ponder the phrase, parse the image, appreciate the shifts in tone and sound as layers are added, and appreciate the unexpected places where the stanzas stop, where they jump to, where they land. Beauty, for me, is a vague and useless term when applied on such a broad scale--as I mentioned before it's more compelling to discuss how successful don't think the artist delivers a set of redecorated clichés about affirming life that experience proves to be patently false. Yes, the artist ought to challenge expectation, and the audience would need to argue how well the craftsperson succeeded in the attempt.