Reading the changelog you can see that this is a fairly large release when you weigh it against previous versions. You can also see that it has been one of the longest periods of time between releases. This is most likely due to Todd Ditchendorf, the developer of Fluid, taking on the much more challenging task of creating a full-fledged Web browser called Cruz.
On the Fluid blog Todd mentions that "This release incorporates most of the features and fixes that went into Cruz 0.1...". That makes me happy, since I'm not a big fan of Cruz, but am a big fan of Fluid. At least the work Todd is doing on Cruz doesn't mean that Fluid is being left behind. Kudos to him for developing in this manner.