"[...]a large percentage of our customer base just didn't get the idea of font activation and why such a thing was ever needed."
However, in a recent turn of events Bohemian Coding released a brand new app called Fonts – Simple Font Organizing. It is based on a completely new build and should not be looked at as a simple revamp of the now defunct Fontcase. Surprisingly, some of the key features of traditional font management software have been removed, most notably: font (auto-)activation. Instead, your Fonts Collection is now directly synched with Font Book and other Mac apps.
As for the visual side of things, the user interface has adopted a fresh flat look and feels like it just broke out of iOS 7. It may take some time getting used to it but hey why not? The designers might have started a new trend right there.
In my book, this doesn't qualify as a font management app, because a key feature is missing: font activation. For me, this is a deal breaker. The developers complained that people did not understand why they should use Fontcase back then, but now that a major feature has been removed (among others it seems), I don't see how you could attract new users this time around since all it does, is give you a preview of your Font Book.
It's wait and see for now. I'm not pulling the trigger unless some significant changes are made in the future to improve Fonts.