We have five stickies already, and there's a lot of scrolling going on (and with six - you couldn't view the forum as easily). Official Download Discussion was never stickied in Fifth Generation, only in B2/W2. I plan to update the FAQ anyway with all event information at some point, and there's only a few left for Generation 5 before Generation 6 hits, and most of the time events aren't discussed too extensively.
The thread itself has only gotten around 25 posts in a time space over a month too, which doesn't really warrant taking up sticky space, compared to the Travel Journal which is used every few days, the Quick Questions threads which are necessary and the FAQ/Rules which are also necessary. The thread can be revived as much as possible, though, despite it not being a sticky, and it's easy enough to find if you're looking for it. If we stickied everything it'd get harder to scroll and as staff we aim to have as little stickies as we can to make forums look less overwhelming to members.