So, this whole thing started out as a brief rant that's been in my head for a couple of months. Also, I wanted to get rid of those tabs that had been on the far left side of Firefox for ages. I'm not even sure why I posted it to HN; I just did it and then intended to head out the door afterward, except that all of a sudden my web server became unresponsive.
Anyway: the ability to get results from the past year is great, and I was totally unaware of it. I'll update my post shortly with a note about that. Having something like that sticking right out on the left-hand side would be even better. :-)
I think I often see people complaining about search quality (here, and in the other HN thread I linked to from about a year back, as examples), but if you ask them about the specifics of the search, they don't remember. I think that's a problem that needs to be solved somehow. Although it's at least partly laziness on the user's part, I think Google could view this as a huge amount of potentially beneficial information that they're missing out on. Trying to improve search results without knowing what problems people are having with them is challenging, at least.
It would be nifty if there were some kind of "these were not the search results I was looking for" quick form linked from certain types of search results.