Hi Sean,
1) Lots of people take speed tests seriously, even if they're not a good way to judge a libraries use.
Absolutely true Sean.
2) Making jQuery faster doesn't mean it has to be bigger in size, only more clever.
Actually that's not 100% true. As Klaus mentioned, there are boundaries that you will hit where maintaining a small file size needs to be sacrificed in order to achieve greater performance. The core team has looked seriously into this, especially in light of all of the speed tests. For example, you take DomQuery from the Ext project, which at one point was the fastest selector engine out, and its 9K minimized by itself. Thats 9k without all of the extra EXT functionality.
3) Development time is important, but so are viewer's patience. Slow code is never good.
The thing is that in reality, jQuery isn't slow. Unfortunately, these tests paint a picture that really doesn't match reality. I have yet to see anyone provide a real-world example where jQuery is so slow at DOM manipulation that the user experience is unbearable (or anywhere near that).
4) People's perception of a jQuery is what will ultimately decide it's fame.
This describes the results better than point #3. The perception, based on these tests, could certainly sway someone from using jQuery even when there's not necessarily a problem.
Rey...
