Hi David,
Almost certainly a subset (via templates).
Not least because it keeps growing.
The DatePicker is a good example. The basic UI Widget support is in, but only a handful of the options supported by jQuery are in the template. (Quite simply, because there are too many options). However a specific embed point is created so you can set whcichever options you like. (And I'll be adding a property for a "global default for date picker options" as well.
So this concept will be applied to more and more of the UI items that are available, as I get around to coding support for them.
Cheers
Bruce