Vaudeville is making a comeback, much on the periphery, everything considered (5,4)
I believe the answer is:
music hall
'vaudeville' is the definition.
('music hall' can be a synonym of 'vaudeville')
'is making a comeback much on the periphery everything considered' is the wordplay.
'making a comeback' is a reversal indicator.
'on the periphery' means one lot of letters goes inside another.
'everything considered' becomes 'all'.
'is' reversed gives 'si'.
'si' placed within 'much' is 'musich'.
'musich'+'all'='MUSIC-HALL'
(Other definitions for music hall that I've seen before include "Late 19th century entertainment, and the theatre it took place in" , "Live entertainment" , "theatre of a sort" , "Form of variety" , "Mainly C 19 variety entertainment" .)