Gaseous: adding FI to an R22 would have many problems - and I don't think anyone outside the Robinson factory has the qualification or experience to comment. Including me. I'm sure if you email Pat Cox or Frank, you'll get an answer.
But - cost, certification, weight, space are all on the menu I'm sure. The Raven II engine is very different from the I inside.
But it's this "automation" thing that gets me. If we were to follow your idea the whole way, we would have a fully-automatic helicopter which required nothing from the pilot other than, possibly, flight control input.
We have developed cars along these lines. Owners are coddled by technology - they don't need to scan instruments because there aren't any. They don't need to chnage gear, because they've got an auto box. They don't need to check any fluid levels because the car will tell them when it needs something. In safety, we've surrounded them with airbags and ABS.
Has this made motoring safer ? No. For some drivers it puts them into a "sitting room" environment and they stop paying attention. They get bored - so they fill their time making calls and listening to the ICE. They think they're bombproof with their safety devices - so they start to drive beyond the limit of their capabilities, thinking that the car will rescue them. People truly believe that airbags will save their life.
Transpose this to helicopters and lowtime PPLs and you have a recipe for disaster. Carb heat requirement means that a pilot has to do a regular instrument scan to check for the "yellow" arc. And he may spot something else going on. Additionally, awareness of carb heat requirements means that a whole string of information processes through the pilot's brain - OAT, MP, governor, aircraft performance. It keeps the mind on the job of flying.
I reinforce this argument with the CAA's argument on power failure. A battery must be capable of supplying the aircraft with full power for at least 10 minutes - because the CAA think thats how long it would take a PPL to spot the alternator fail light.
If all the instruments were simply reduced to an "on report" status, I'm not all certain that the cockpit would be a better place. (Yes - I know that's the way it's gone at the expensive end. And don't they all just love their FADECs and EFISs ? No.)