China Southern is replacing A330-300 to Tokyo Haneda

I know this could be both good or bad news given that China Southern's 787 is cramped in Economy even though is newer than most of their A330. Business Class feature the same product except that some of their new A330s have staggered Business Class like their 777 and removing First Class.
China Southern

Per Routesonline today, China Southern is replacing their A330-300 with their B787-8 for CZ385/386, the 737 flight remains the same. This is going to effect from 29Nov.