And there are tools. Poets should read poets, should understand meter, should be able to employ poetic device, should consider line breaks as important as the words. Poets should KNOW words; they should be able to express sentiment without using overt sentimentality. I could go on, but my fingers are tired.
but it's important to remember that none of what you (correctly) point out above relies on formalism.
in fact, to deny a poem can be so without formal structure is to ridiculously assume that poetry burst into existence fully-formed, already with structure. surely this is not the case. surely, poetry existed as a very separate thing from prose (indeed from conversation) prior to being formalized.
this were times of a mostly illiterate populace that depended on memorizing verse to retain it or perhaps having it read aloud to them, both of which were enhanced by predictable rhythm and meter.
in the age of near global literacy, in the age of the printed page, poetry can do more. it can play with the eye as much as the ear.
furthermore, as with the visual arts, as with music, as with theater, convention is made less important by accessibility in our age. poetry is no longer only about exalting god or exalting heroes or exalting love (though it can certainly be so), it's about anything and everything.
with this freedom comes the freedom (and rightly so in my opinion) to break the walls imposed by history.
remember that with any formal school came a history whose shackles the young turks cast off. they were all revolutionary and without the sentimentality many of us now harbor for them.