Just like USA would be a very different place if 300M people had a vote that mattered, China would be a very different place if 80M people had a complaint mechanism that mattered. We'll never hear of the city clerk who complains about the excesses of the latest giant project imposed upon local citizens. There are probably hundreds of those people, and they have all been taken care of. (Most of them in standard bureaucratic politicking fashion: "she said this terrible thing about Xi" "there is corruption in his office" etc. Kicking down is a great way to move up, when an official a couple rungs up approved the project and wants the complaints to go away.)

Yes because they read all missives personally. And no one ever interferes with those missives or those who send them. And no one ever lies in them for personal gain or joy in chaos.

Quick, do a good job and renovate everything, hide or move anything annoying or embarrassing while the boss is here is part of Chinese management everywhere from Xi Jinping on down. Supervision and management are hard, especially when your subordinates are constantly shading the truth and covering things up.