Fans of Nova Launcher and WidgetLocker have long had support for bubble-style unread counts on some app icons thanks to TeslaUnread. The newest beta version of this app includes preliminary support for a ton of new apps, but you'll have to opt into the beta.
Here's the changelog, which is mostly just a list of newly supported apps.
- Hangouts (requires Hangouts v2.1)
- Notification Bar Watcher (Android 4.3+)
- Extract unread counts from Notification Bar notifications from virtually any app
- Facebook (Experimental, unsupported on HTC Sense)
- Press RSS (Experimental)
- Many bug fixes and optimizations
- Fixed FCs (4/29/14)
There are some caveats, of course, but this should make those little bubbles much more useful. Of particular interest is that ability for TeslaUnread to extract unread counts from the notification listener, which should allow it to work with almost any app. But remember, this is a beta and you need to be using WidgetLocker or Nova Launcher Prime (both paid apps). Get in on the beta here, or download the free beta APK.