Developing a bad role that's very attractive! (8)
I believe the answer is:
adorable
'very attractive' is the definition.
(I've seen this before)
'developing a bad role' is the wordplay.
'developing' indicates anagramming the letters.
'a'+'bad'+'role'='abadrole'
'abadrole' is an anagram of 'ADORABLE'.
'that's' is the link.
(Other definitions for adorable that I've seen before include "worthy of love" , "Endearing" , "Inspiring great affection" , "Very charming and attractive" , "Very pleasing" .)