I'm going to go out on a limb here and state herewith that "a good poet" can be defined as an individual who writes one or more good poems. Now as is stated above, the quality or goodness of a specific poem is a very subjective evaluation, meaning that most of it is left to the person doing the deciding.
Thus, that Edgar Allan Poe wrote poems is an undeniable fact. Whether or not these poems are good is up to the reader. This reader (I) will say right now that these poems by Mr. Poe are good poems:
"The City in the Sea"
"The Conqueror Worm"
"A Dream Within A Dream"
Indeed, the last listed poem, "The Raven," is so good that it has withstood the test of time (over 150 years) and almost any literate person knows of it and may even be able to quote some lines from this dark, mysterious, poetic... dare I say it... masterpiece:
Once upon a midnight dreary, while I pondered, weak and weary,
Over many a quaint and curious volume of forgotten lore,
While I nodded, nearly napping, suddenly there came a tapping,
As of some one gently rapping, rapping at my chamber door.
"'Tis some visitor," I muttered, "tapping at my chamber door-
Only this, and nothing more."
Yes, such writing makes Edgar Allan Poe, at the very least, a good poet.
Quoth the Raven, "Nevermore."