Dash,
You brought up a subject, people have discussed it with you, you've rejected opposing opinions, and you don't seem much interested in doing anything but sticking to your own view.
Many of us here have been holstering guns of all types for decades.
I carried a SIG P220 back in 1982 as a duty pistol. I've carried a Smith 4516 which did have a safety but I carried it off-safe, I've carried various Glocks off & on since 1988.
DA & DAO pistols certainly were around when Cooper condensed his four rules, those rules are every bit as valid today with what you feel are "new" designs as they were back then.
Bottom line is: You get in the habit of sticking your finger inside a trigger guard on holstering, you are creating a hazard that did not previously exist.
You are complicating what should be a simple process, you are creating an opportunity for stress or inattention to cause an AD.
You are NOT making the holstering process any safer.
If your idea did, don't you sorta think the pros would be teaching & using it?
Call Bruce Gray at Grayguns & ask him what he thinks of applying your idea to the DA and DAO SIGS he uses & teaches.
Call the SIG/SAUER Academy & ask them the same question.
Call your local Glock instructor, or attend a Glock shoot with a Glock company instructor, and ask him what he thinks of the idea.
Call Gunsite or Thunder Ranch & propose your idea.
Find four or five PDs in your area that authorize the guns in question, see how many agree with you.
And I won't even bother to bring up over 100 years of DA & DAO revolvers, since MLeake already has.
Like it or not, your idea is a bad one.
Denis