Man of taste might rue alteration to long poem (7)
I believe the answer is:
epicure
'man of taste might' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'rue alteration to long poem' is the wordplay.
I cannot really understand how this works, but
an anagram of 'rue' is 'ure' which is located in the answer.
'long' could be 'epic' (as in an epic story) and 'epic' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for epicure that I've seen before include "Choosy eater" , "Gourmand" , "Person with fastidious tase in food and wine" , "Connoisseur" , "Lover of fine foods" .)