what could have been done more?

 "And now, O inhabitants of Jerusalem, and men of Judah, judge, I pray you, betwixt me and my vineyard." Isaiah 5:3 KJV"

What could have been done more to my vineyard, that I have not done in it? wherefore, when I looked that it should bring forth grapes, brought it forth wild grapes?" Isaiah 5:4 KJV 

I have some suggestions, but it's probably a rhetorical question. God isn't too keen on improvement ideas.