The problem I have with Jetpack is that it is bloated and too heavy to make it worth installing. It slowed down my website dramatically and caused errors.
Moreover, adding such a large but mostly unnecessary code to a WordPress installation is a potential stability and security issue.
I don't need Beautiful Math, hovercard popups, an extra CSS editor or in fact most of the functions provided by Jetpack (and, oh dear, "many more to come!"). But just a couple of the components would be useful to install.
So why not break down Jetpack into separate plugins? It would be an elegant solution and would let people select and install only the components they need...