The golden period of the food critic was the time of Jonathan Meades and Craig Brown, pre A A Gill. Now I think critics have had their day to some degree. Reviews are more about, "How clever can I make this piece?". They'll write anything for effect. Take Gill. He's a wonderful writer, I read him every week and have a chuckle, but if you want to know about the restaurant he's just been to, you just have to read the last two paragraphs.
One failing is that I don't think enough attention is paid to a restaurant's atmosphere. For critics it's just about food, and they don't say why it's buzzy or busy. In today's voyeuristic society, a lot of people don't just go to a restaurant for the food but for its ambience: how trendy it is, who they might spot. If the food is good it's a bonus. When it comes to restaurant criticism no one is doing what 'Grazia' does for the fashion world.
The other problem is that if critics all go to the same restaurant, like a new Gordon Ramsay or whoever, they all say exactly the same thing. But this business is subjective, not objective; you can't tell me everyone has the same palate.
Restaurateurs also need to change their approach. Unlike in the theatre, when critics are barred from going while a show is in preview and all the tickets are cheap, most restaurateurs don't have a training period when they open a new restaurant. They need a period when the food is half price and they say no to the critics. But most are so desperate for money that they rush to open and expect it to be perfect straight away.
I think the integrity of most food critics is pretty good, but I believe they are too scared of the big boys. They're not prepared to take on Gordon, or whoever. The flip side is that most restaurateurs are shit-scared of food critics. Not me. I'm too long in the tooth. I've given up on most of them.