Oh, it's not that big of a deal. Minecraft devs are talking about it all the time now, for example in the 14w17a description.
Mods are going to be resource packs. Minecraft has had the capability to load classes from resource packs since 1.6, actually, that's how the forge installer works with the new launcher.
FtB mod packs peaked with the Mindcrack pack, ever since then it's been a steep down hill.