Artist wants composer, but not a novelist (2,5)
I believe the answer is:
el greco
'artist' is the definition.
(I've seen this before)
'composer but not a novelist' is the wordplay.
'composer' becomes 'elgar' (Edward Elgar).
'but not' is a deletion indicator.
'novelist' becomes 'eco' (Umberto Eco).
'elgar' with 'a' taken away is 'elgr'.
'elgr'+'eco'='EL GRECO'
'wants' is the link.
(Other definitions for el greco that I've seen before include "Sixteenth to seventeenth century Greek-born Spanish painter" , "Famous painter's nickname" , "Domenikos Theotokopoulos" , "Spanish Renaissance painter" , "Crete-born Sp. painter" .)