Regarding git vs af, if I could use the git already installed in my computer, and by simply adding my SSH key into AppFog system, I could avoid using `af` gem and Ruby altogether. Otherwise, I would have to install Ruby just for this purpose. But this is just personal taste.
Other PaaS such as Heroku or OpenShift allows you to set up a custom app. For example, you can create your own app type in Heroku's cedar stack with buildpacks, or the DIY app in OpenShift with supports for hooks.
Erlang probably isn't on the top of the priorities list, but I'm looking forwards to it.
No integrated git-push deploy (I know you can use a gem with an extra instance to do that, but still). No SSH into your app. No custom app. Extra runtimes are there, but old (Erlang, for example), and no idea how to use them.
It'd easier for a repo hosting service provider to provide an integrated planning tool. It'd be easier for customer too. Of course, only when they do it right.
I love Trello, but it's supposed to be generic, and thus, not easy to use it as a Kanban board (limit number of cards per list, etc) out of the box.