I'm not certain but I'm pretty sure that anything you can do with bubbling you can do with capturing and vice versa.
The idea that you'd have some events bubbling and some capturing in the same app sounds like a good way to make things very confusing. What I'm saying is, I don't think bubbling versus capturing really matters. What matters is that you pick one and stick with it.
W3C's APIs often contain this sort of thing where they have a lot of features that nobody really cares about. Perhaps this is another example of how good defaults can remove the need for configuration or even whole features.
