I propose to adopt voting system to make things better (7)
I believe the answer is:
improve
'make things better' is the definition.
(to improve something is to make it better)
'i propose to adopt voting system' is the wordplay.
'propose' becomes 'move' (moving is a kind of proposing).
'to adopt' means one lot of letters goes inside another.
'voting system' becomes 'PR' (proportional representation).
'move' enclosing 'pr' is 'mprove'.
'i'+'mprove'='IMPROVE'
'to' acts as a link.
(Other definitions for improve that I've seen before include "reform" , "Change for the better" , "Enhance" , "Train" , "Ameliorate" .)