Bad reviews don't just help me find the contractors that would light my house on fire, rob me and piss on the ashes they help me find the ones who only deliver without difficulties 90% of the time so I can avoid being part of the 10%.
Also people would still be able to write negative things while giving what amounts to a 4 or 5 star review on your site. People after all love to complain. Being able to filter or sort for the bad reviews helps me obtain that information whereas it would be harder to do. In effect all the same negativity would likely be there just without the extra metadata.
For something like a contractor working on your house, yea it's important to see those reviews. For a meal? I'd rather just take a chance based on a lot of people saying they had a good time. It's what you do anyway when you check out a new restaurant based on a friend's recommendation or just on a whim.
And the whole point is not to have any star system, you either liked it or loved it and that's it. No opportunity for commentary so if you want to complain, go elsewhere. The tagline I dreamed up was "Haters gonna hate, eaters gonna eat."