The reason why it hasn't been done is probably the frequency of big hands - I believe that holding 22+HCPs (or QTs and/or controls, or however you define your strong 2♣ opener) is about a 125-1 chance - so we all get by with what is out there, be it controls, 2♦ waiting (positive or negative), or whatever takes our fancy.
I'm personally not a fan of 2♦ waiting but I do see its merits - rightsiding a contract, for example, preserving a level of bidding, etc - but it also gives a partnership headaches as the opening bidder sometimes cannot tell if his partner is bidding as a positive/semi-positive or a negative (except where there is a 2NT double negative incorporated into the mix.)
SAYC, for example, and this is what I read, blindly says that an opening 2♣ bidder should feel comfortable to bid to 3♥/3♠/4♣/4♦ on his own opposite a negative except with a balanced hand.
What it doesn't take into account is the majority of the hands that need to open 2♣ do not have long self-supporting suits and controls outside, and are more likely to 5-4-3-1 or 5-4-2-2 or similar shapes, and only work when a fit is found. (Also, when those 5-4-3-1/5-4-2-2, etc hands tend to be top heavy minorsuitwise they become awkward to bid.)
Even although I go against popular opinion, I actually like controls as virtually immediately (but not always) the opening 2♣ bidder - who should technically (and this is my opinion also) be in charge of the auction and final contract - can see where the hands are potentially heading. If controls are good enough for Jimmy Cayne (JEC) and his team they are good enough for me
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The other problem I personally encounter is any positive response to a 2♣ opening automatically guarantees game being reached but not slam necessarily. There are plenty of hands in that positive hand territory (7-11HCPs as a rough example) that do not fit well with opener, but as opener has received a positive response he goes slamming, or perhaps worse, responder takes over the auction bouncing the partnership into an unmakeable slam..
The reason why I mention who controls a 2♣ auction is important as if you look at the Precision system it is invariably the opener who is in charge of the auction - not always but on the majority of occasions. That's probably one reason why the 2♦ waiting bid was introduced so that the 2♣ opener is primarily in the driving seat once again.