The fact that it needs to be operated at all is the flaw
Then why stop at carb heat? What’s so special about carb heat that makes it a flaw? Large ships don’t have any handles or wheels or anything, it’s all automatic point and click because this is more effective and it is safer. Yet I wouldn’t call a manual throttle and a steering wheel for a design flaw. It depends what you want I guess, but if the point is exclusively to get from point A to point B, then clearly the very concept of having a pilot in the loop is a “design flaw” because a pilot is a weak and unpredictable link.
Then why stop at carb heat? What’s so special about carb heat that makes it a flaw?
I don’t think it should be banned either but it is clearly a design flaw. A mechanism designed to deliver fuel to the engine frequently fails to do so causing engine stoppage typically at low altitude.
Try getting something like that certified now.
There are many reasons the accident statistics of drones are terrible, but I think we’re still a long way from the point where pilotless aircraft are safer than piloted ones. I’m sure that day will come sooner or later.
Maybe automatic control of fuel tank selection should be mandatory too 
I have to admit to being mystified that carb heat control is somehow an issue for some people, but to each his own. Every owner can and should decide what they want to buy and fly. In my hangar I like the fuel system that requires no fuel pumps better than the fuel system that requires two of them and pressurized fuel lines.
In your opinion. In my opinion it is a flaw, however simple it may be to operate. The fact that it needs to be operated at all is the flaw.
What about fuel systems that are not gravity fed? Flaps, retractable landing gear…? Not to mention engine alternate air controls, alternate static source, fuel selectors…?
Ah the menace of fuel selectors! Beloved of bush pilots I believe.
Sometimes I wonder how aviation ever got to evolve past Gnome rotary engines and castor oil.
Hey, just voicing my opinion, no need to pick the whole concept apart.
What does the Carb heat and mixture control (to name a few) add to the flying experience that makes them so important to protect? To the point where it is better to keep them for all future designs than to remove them?
I have very limited experience of aircraft in general, only 25 types or so, and most of them have had mixture controls as well as carb heat.
The few types without have been very easy to operate, yet provided me with exactly the same pleasure of flying.
A fuel pump is a necessity due to a low wing design, and there are all kinds of reasons why you would want a low wing design. Why would you want to design
an engine that requires carb heat sometimes?
What does the Carb heat and mixture control (to name a few) add to the flying experience that makes them so important to protect?
Pilots like pressing buttons and moving levers :-) Do they still sell new aircraft with IO-360 or whatever engines that still require carb-heat, or are they all fuel injected? I agree with what Jason says – I wouldnt ban them, but they have been the cause of a number of serious incidents that could have been otherwise avoided (could be applied to a number of other things though I guess).
What does the Carb heat and mixture control (to name a few) add to the flying experience that makes them so important to protect?
The only way to remove carb heat is to install FI, mechanical or electronic, and this adds complexity. Electric pumps etc.
Of course you can do as Rotax does and fly with carb heat on constantly and loose 5-10% power.
It’s just a trade off. That simple lever enables full power when you need it, even with a carb.
