Dear Kay,
Over on one of those other threads you offered the very excellent advice to make much out of the moments of everyday metta. You’d better believe I’m wringing every drop of jolliness out of your kindness here! Much thanks to you! 
In yet another thread you beautifully advocated permitting happy, easeful, loving disagreement, so here I’m well aware I have the great gift of plenty of room to comfortably disagree. The only trouble is, I don’t!
You’ve drawn out such incredibly valuable details that I certainly don’t have any will to counter. In my own terms, the points you’ve set out are worth a whole lot of reflection (not least—coming from the pragmatic view point I’m ever fond of—as they are all excellent means, if a person is willing, to help cultivate the joy I believe is foundational to go further with the practice).
I have a very keen sense of all three key points you mention, and, as an aside (so long as you don’t tell anyone because in a way it’s a bit embarrassing), funnily enough when I first came to Buddhism and first had to puzzle over this “Buddha, Dhamma, Sangha” thing and how on earth I could relate to it, between the Buddha and the Sangha I actually found it much easier to generate meaningful, joyful feelings around the Sangha (I never had to do any work to recognise the brilliance of the Dhamma).
This was because of exactly that ‘carrier of the teachings’ point you mentioned (I’m a “go to the source” kinda gal, so very quickly headed over to the suttas and immediately feel in love with them—almost a little bewilderingly so—and then started thinking about the technical feat of preserving them through the ages and the diligence and care it required and naught but gleeful gratitude to the Sangha resulted).
The reason, however, I wanted to make clear how very much I do not disagree at the start (not merely for the sake of politeness, but—again, with that practical interest—for recognising and wanting to emphases the great value of the perspective you’ve contributed) is to stress that when I make the following note, I put it forward as companion rather than contradicting thought.
When thinking of taking refuge in the triple gem as a practice of sorts, for me personally, I feel the need to “keep the bar high”, so to speak. I should probably have to mention that in terms of sensing places of true ease in this world, I’m pretty resolutely untrusting (with all sorts of qualifications) and this psychological background undoubtedly heavily influences the way in which I orient the notion of refuge.
To me, when I consider the act of taking refuge in the Buddha, my feeling is that the Buddha’s accomplishment is perfect. Likewise, I feel that the Dhamma is perfect. Both of these things offer perfect security.
However, when I consider the conventional Sangha (the worldly Sangha governed by rules bound to and concerned with a deeply imperfect, delusion-led world and further that is pretty much guaranteed to breakdown and completely fall apart at one—hopefully, very distant—point or another), I find that it is the very best of the best supports, but it is imperfect, it is corruptible (witnessable from the Buddha’s day to this), it does not meet the same standard as the other two aspects of the triple gem.
I’m not quite convinced that the Buddha would invite me to take refuge in that which is unstable. By my reading of the suttas, very, very clearly, the Buddha encourages seeing the extraordinary benefit of supporting the worldly Sangha (which in turn naturally entails reflecting on its immense value); but I hesitate over the idea that the Buddha would promote seeking ultimate security in that which is inherently insecure.
The timeless Ariya Sangha does offer a perfect security, on par with that offered by the Buddha and the Dhamma. It is an unshakably reliable refuge. I’d be entirely willing to concede that mine may be an excessively quirky reading, but at least one aspect I feel is present in the security offered by the Ariya Sangha isn’t only that there are these brilliant people in the world to help inspire and carry the teaching forward, but it is just for the demonstration of the idea that people really can, have and do realise this path. To put it in a yet more quirky way, one can dwell completely safe in the notion that, “as it has done for others, the possibility of freedom applies to me, too.”