First, terms such as "power," "originality," and "individuality" are not entirely objective terms, although of the three, the first two are most able to be analyzed historically.
In terms of originality and individuality, Poe has a very distinctive poetic voice, relying quite heavily on assonance, alliteration, and other figures of sound. Thus, we can argue that in terms of literary style, the poem is original. In terms of subject matter, this is a love poem, in which the lover is mourning the death of the beloved. This is not a particularly original or unusual subject, although Poe's emphasis on the extreme youth of the beloved is distinctive and he frequently returns to the subject of the death of a young, beautiful woman. The conceit of blaming angels for her death is sufficiently unusual to be termed original.
While some people may find the poem emotionally powerful, others may find that its technical virtuosity reduces its emotional impact. It is a very popular poem which suggests that many people do find it powerful, but others may not.
More than anything, this poem represents the struggles of power in relationships of the heart. The young couple in the poem are doomed from day one. They are criticized when young for being too young - the adults are superior to them and limit their power. They are doomed as adults by the social classes, which limit them because of their different stations. Finally, they are doomed by the jealousy of the angels, who steal the beautiful Annabel Lee from her lover because of her beauty. In summary, the lovers have no power and the world around them - including the heavenly world - has all the power.