There are a lot of features you could not possibly change faster than the time it takes to pull out a cell phone that given that they are buried in a menu somewhere. I'm not suggesting everything be offloaded but I think it's pretty safe to take something like the filename formatting out of the camera menu. You're not going to change that in a hurry. And frankly the argument that every feature of a camera needs to be in a menu just doesn't match reality. NOBODY needs every possible feature of the camera on the little screen. NOBODY is going to change a lot of those settings "quickly while holding the camera with both hands". Some they will. Most they will not.
You are joking right? From hitting the menu button, I can usually find what I want to change and change it in about 2-3 seconds. WiFi to cellphone? First I have to go into the menu to enable WiFi (I don't leave it on due to battery drain). Then you have to download the app onto your smartphone. Then you have to find the camera's WiFi on your phone and connect to it. Once you do that, you can start the app, which will search for the camera. Once it finds it, then you have access to your camera. I have found that this takes about 10-15 seconds, if it was previously setup. For a first time setup, try several minutes, since you'll have to create and enter a password, pair the devices, etc.
If I am going to use my smartphone to take pictures of family (use it as a remote trigger since they are expensive), I make sure to get my camera and phone setup ahead of time so people don't get upset that it's taking too long to take the pictures. But the menu? Mere second or two. The smartphone access is a nice feature, but it is NOT a replacement for on-camera features. I mostly use the WiFi feature for sending photos from camera to phone to online (facebook or photo share), rather than having to use the old school approach of connecting to computer, or even removing SD card and using SD card readers.