Just to clarify this: under pre-sixth edition rules, Reconnaissance didn't allow the player to untap a creature after combat damage. There were only two steps during combat that allowed instants. First one between declare attackers and declare blockers; second one between declare blockers and combat damage. Activating Reconnaissance outside these steps was impossible.
Here is Matt Tabak's explanation of the latest change.
Reconnaissance (functional)
Previously on Oracle Theater...the evil constable discovered a technicality that allowed him to turn the malt shop, so beloved by the townsfolk, into a hardware store, reviled by the townsfolk
"But we've always bought our malts here," they cried.
But the evil constable was undeterred. "This paperwork here says this location was originally designed to be a hardware store," he explained. The fun the townsfolk had been having at the malt shop seemed beside the point.
And so the malt shop became a hardware store. And the people were sad...
Reconnaissance was given a timing restriction in the last update to enforce the original intent of the card. You send your creatures out there, see how the blocks go, and then pull back the ones you want to. Changes to the turn structure since the card's printing had given it new, unexpected functionality: now you could untap your creatures after combat damage had been dealt, giving your creatures a sort of vigilance.
It seemed a pretty easy change to make at the time, but I screwed up in at least two ways. One, because the card had the "pseudo-vigilance" functionality for so long, it pretty much became the card's identity, and at some point you have to just respect that. Two, cards sprouted up around Reconnaissance that included cards that were designed and developed under the modern turn structure, like Ith, High Arcanist. Surely I wasn't going to errata Ith. Hrm.
Ultimately, I'm here to make Magic more net fun. The Reconnaissance change, while well-intentioned, made the game less fun for some people and more fun for almost nobody. So, as I suspected during the last Update Bulletin, I'm reversing course. Sorry for the scare everyone. Thanks to everyone who provided feedback (some hilariously colorful; oh, I wish I could share).
...after quite a lot of resistance, the evil constable tentatively sipped his malt. It was good, and in an instant the error of his ways was made clear. The malt shop would live again!
But if you're a textualist, then high-five bro. Let's play 4Vale.dec.
I guess it's just non stealth errata, more or less, but it's always annoyed me in a way similar to the Reconnaissance change.
Here is Matt Tabak's explanation of the latest change.