1) Because current_time is not normally available in a conditional, we need it as a variable to make it available.
OK. That makes sense. Is it safe to assume that it will be added to next version of EE as a standard conditional variable?
1)2) There is no problem with date_heading; the problem, which we clearly demonstrated in the tests, is with your conditionals. If you had no conditionals, the date_heading would always work. Anything you put in the conditionals does not show up for the first iteration because of how it is comparing. This is not a bug -this is the conditional displaying exactly what and when you told it to.
Hmmm… I think {date_heading} should evaluate only what gets passed to it, there by reacting to the first entry it encounters regardless if it wasn’t the first entry the weblog:entries tag found. Yes, I got the results/data I wanted but {date_heading} should, in my opinion, trigger based on that first record encountered. To me {date_heading}, in this case, knows too much about what the weblog:entries tag returned and is reacting, or lack there of, before it’s being asked to.
3) Yes, but it’s a plugin currently. =)
Oops, my bad. 😉