OK, I'll bite... Here's my thoughts...
1. All things like USB3, WiFi, Bluetooth, Gigabit Ethernet, GPS, WiMax, Integrated Broadband, etc are simple small chipsets that are fairly modular and easy to integrate into most designs given the effort is put forth in the firmware to write code to address them properly. (Firewire, Thunderbolt etc from Apple are usually avoided due to the excessive patent fees they demand for inclusion.) The design problems are usually issues with power, heat and RFI Interference. The cost of the chipset could be a factor but I doubt it. It's more the cost of everything else that revolves around adding the feature... circuit board design, testing, etc. Add more stuff to the mix, more things can go wrong.
2. Tethered Shooting has its place but IMO, Wireless Tethered Shooting is the future however it is implemented. Same goes for network access. And Flash Control. Honestly, wires are a pain but unfortunately they are less expensive and more reliable if proper care is observed with the connections and strain relief is used. Once wireless solutions evolve to the point where they are totally reliable, inexpensive and power efficient, no one will use a wire if they don't have to.
MY ideal DSLR would have fast WiFi, reliable integrated wireless flash and shutter control that is universal (not proprietary) and even maybe wireless charging. Maybe bluetooth too? Most of the roadblocks are power related IMO. I am anticipating the day when the flash has a hot shoe on top for backwards compatibility but the camera easily communicates with the flash wirelessly (without a master flash) and I can simply grab the flash and move it around while shooting without extra devices (ie PocketWizard) attached to both or the need to have a master flash on the hot shoe just to talk to the wireless flash. I was sort of expecting the 5DIII or 5DX to have this but unfortunately, all they did was add some RF to the new 600RT flash and charge a mint for it. Big whoop. Not much improvement there if you ask me. The writing is on the wall for the need of true integrated wireless flash control. Why doesn't Canon just do it right already??