Gojiberry: Terrible job. I asked for specifics and you repeated your general statement with no proof. Unproductive additions aren't going to advance any ideas. Thanks in advance for putting thought into your future responses and not knee-jerk ad-hominem attacks about how I am not thinking my way through the subject.
Loveshðck: Thanks, you presented an actual reason why you think what you do. However, the runes refresh as Death Runes, and only fully depleted ones. I have thought about other instances and haven't come up with any. Your example:
[...] you can refresh the wrong rune rather than refreshing that Death Rune you were hoping for
is one that occurred to me and was dismissed.
This is because: If a blood rune is fully depleted, that means that both blood runes are on CD; if one is, as you suggest, 1/2 second from returning, then returning that one would be unfortunate, since waiting would provide a possible greater return. This is an example of tooltips leading to misinformation in theorycrafting. While it does say "activates a random, fully-depleted rune," the randomness is only across runes, not within them. If all your runes are fully depleted, then its random whether its a blood, frost or unholy rune that is activated into a death rune.
If, for example, your blood rune is chosen, one of which is only 1/2 second from returning, the rune that has not yet begun refreshing will be returned. I hope its clear from experience what I mean when I say "the rune that has not yet begun refreshing." What it means in a practical sense is that the rune with a full 10 seconds (or whatever the number may be, depending on spec, presence, etc) will be the one to activate, and not the one 1/2 second from returning.
In general I agree with you about the evils of macros, and rarely use them in combinations like these (unless its farmed dungeon/questing content so I can mash buttons and catch up on How I Met Your Mother). My interest here is to see if others have real, measurable concepts or data to show why this wouldn't be as good as dancing runes, timing Taps for something other than frenetic button-pushing-fun, or letting runic corruption just speed everything up. Its not to be stubborn, but all I hear is "thats not good obvs, l2p your tank, active is intent so passive must be bad lolz."
Your informations and ideas, I cravez it. Please to share real?