I stopped using Google reviews because it's absolutely pointless with the deleted reviews. So far I've had almost all of my bad reviews removed, even though I always write an honest description of why the food or service was bad. There are some really bad restaurants in my city that regularly go down to 1,x before they remove all bad reviews and it jumps to 4,x again for a while.
The problem is that public ratings will just never be useful. Either you have owners that delete all the bad reviews, or you don't let them delete and good businesses can be review bombed for petty reasons.