The final 2.0.0 file is 12 percent smaller than the 1.9.1 file, thanks to the elimination of patches that were only needed for IE 6, 7, and 8.
Dropping IE 6, 7 and 8 support for a 12% smaller file size while effectively forking your code base for the foreseeable future is a lousy decision. Increase complexity tremendously for what, 3-4 KB when gzipped?
Actually, it's decreasing complexity and getting a happy side effect of a 12% smaller file. It was probably a mistake to add the file size difference as a benefit, as it has obviously confused a lot of people who appear to have perceived it as a primary design goal.
I'll say the size drop is the primary reason I'm going through having the browser tags for ie lt 9, vs other... even though 3-4K isn't much, that's quite a few packets on mobile (though there is Zepto, it's nowhere near complete enough for a lot of needs).
I'm working on some revamped UI at the moment, and so far the script load (uglified, not gzipped) is around 250K, anything that can get that down imho is a good thing.
The article also says they hoped to remove more, but early android browsers became "the weakest link" instead. Presumably, support for them will be dropped without much fanfare as soon as their market share goes below X %.