Wow, the FIA have actualy gone full retard!
They have basically rendered every control on the steering wheel other than the gear change obsolete.
"So Lewis.... uh.... hows your day going?"
This is completely wrong, the drivers will still make hundreds, thousands of adjustments throughout the race. CHanging diff till they find settings they like. Likewise things like going full fuel mode, the engineers make it easier to make the change exactly when it's possible but it's still easy to make.
before a race the engineers and drivers probably know that they can go full fuel mode say around lap 50-51 of a 70 lap race. But depending on how the race goes, being stuck behind someone slow, running in cool air, safety car, whatever, it might be lap 52 or lap 48. The engineer allows precision in when to change, he doesn't make the difference between the change happening or not. If they aren't sure and can't be precise, they'll tell him to turn the engine up on lap 53 to have a safety margin built in. Hamilton will have to remember this is when he's to turn it up or that he can turn it up for a lap or two here and there but have to factor that in to when to turn it up later in the race.
The controls won't change and 98% of the changes done throughout a race won't change. Because there are engineers it's been made easier, why worry the driver or distract them with temp warnings when the pit can tell them, though radios have and do fail. It's easier for a driver to not look at the wheel constantly and just be told in his ear that his right rear is overheating, the engineers may have told Rosberg to shift braking forward but do you think that was necessary. If Rosberg or Hamilton had merely got a display saying warning, right rear temp high, they wouldn't have done things to control right rear temp, you don't think they can figure out to push the brake balance forwards a bit for a while to ease off temps?
Engineers make these changes easier and let the drivers focus on a smaller number of things, they don't in any way make the difference between these changes happening or not happening at all.
The only thing drivers will find incredibly difficult is when it comes to an electronics failure and the obtuse sequences involved for resetting the electronics while still racing.
Because engineers on the radio have been there, how many teams have on wheel temp warnings for various parts is questionable, some may need to add such warnings. The better drivers find the best modes, best diff settings, best balance from within the car themselves, less good drivers who rely on more guidance from their race engineer may struggle more but most of these guys will still be making loads of changes and are fully capable of working around a radio ban without many issues.
In reality with every team building in safety margins to things like which lap to turn up the engine, it will be a pretty level playing field. Everyone will turn up their engine 2-3 laps later to be safe so everyone will lose the same amount.
