There is no sign of this in, for example, the liquids policy. Kip used to go on and on about how they had to implement the "no liquids at all" policy in the middle of the night over the course of a few hours. It was only relaxed when it became clear that people were going to die without essential medicine and infants were going to starve on long flights. More to the point, the duty-free industry and airport shops leaned on the gov't when they couldn't sell drinks, perfume and grog.

The "shoes must be/should be/could be on belts" of a few months ago is another example. Clearly the "shoes out of bin" part was to save time for the TSA in restacking and cleaning bins. Within a few hours, when people here and on PV pointed out the possible damage to shoes getting caught in the machinery, the policy was (partly) rescinded. This is the exact opposite of giving weight to the impact on passengers.
And yet you admit your agency is not infallible. Could it be that they're wrong about this? I believe they peed their pants in August 2006 and are now unable to admit they over-reacted. (That would be pretty consistent with human nature.)

The question is not, as others here have said, viability, but probability. The next time you cross a street, there's a chance you could get hit by a car. There's also a chance that you could be struck dead by a meteor in the middle of the intersection. Which one of those will you take precautions against, and which will you choose to ignore? Why? Stop listening to the chicken-littles at HQ and think for yourself. In human beings, if someone obsesses about absolutely every possibility and treats them all the same, it's considered a mental illness. At TSA HQ, it's apparently a virtue.
And yet your "none" option is "except medical necessities". Does that include infant food? Beverages on board? Meals on intercontinental flights? I regularly spend 24 to 40 hours in transit (from leaving home to arriving at a hotel) - toothpaste, deodorant and moisturiser are medical necessities.
Easier for whom? For elderly people who have trouble removing and replacing them while standing? It's fine for a young, fit person to say "it's no big deal to take your shoes off" but for some people it is a big deal. I'm with JSmith; the rest of the world doesn't insist on this, even where there's a fair amount of concern over terrorism.
And every time you go in, not just the first time each day. Or do you think any screener who wants to bring in a bomb will do it first thing in the shift, rather than after a break?
And yet you said "I believe that means we should try to prevent what we can with all means at our disposal". Does the $3.4 BILLION being spent on a new HQ building counts as "tons of money"?
Seriously, I'm sure you're a nice guy and correct the ones who aren't. For my part, I have never hijacked an aircraft. I have never planted a bomb, brought a gun to the airport, or threatened a FA with my Swiss Army knife. I have no mercy for those that do; I find them despicable and hope they are prosecuted to the fullest extent of the law. But so what? Your colleagues are still going to treat me like I could do any of those things. You shouldn't be surprised if we treat you as if you might steal, yell, threaten or make up rules.
I know full well that your agency is not infallible. I'm asking you to think for yourself instead of just believing everything they tell you.
All people are subject to that element of nature, too. Robert Mugabe is "only human;" Albert Einstein was "only human." That doesn't mean one can't criticize one or admire the other.
You need to get out more. Really. You really need to go to Europe, Asia or Australia on a GSO-LAX-overseas route of about 20 - 30 hours in a very dry aircraft without a break. You will begin to understand why the liquids, etc, that seem "optional" to you are essential to us.
Seriously, come to Australia and I'll buy you 3.39999 oz of beer.