Yeah, I'm pretty sceptical that we'll be seeing any big mods being updated for at least several months. It may also be especially hard for novice modders as well, as I do believe that in the last 1.6.4 source version of forge they changed the build system so that you can no longer view the decompiled source, only you're mod's code.
it's nice to see forge being release to 1.7 as it gives the modders the chance to already start coding their mods for 1.7, but I agree on that it'll be a while before we even will see a stable release of forge for 1.7, and for mod developers to actually start releasing their mods for 1.7
personally I hope 1.6.4 will be like 1.2.5, where mods have the time to do their thing and the userbase is able to do more things with the mods, like modpacks or perhaps a new FTB Insanity map?
I almost wonder why the modding community at large bothers with 1.7 at all. Why not take Christmas off, and start directly on 1.8 when released this spring? Snapshots will apparently be out in January.
Then again, the actual 1.8 release can still be months away, and I suspect the conversion would take a long enough time that by the time it is ready to launch, 1.9 is just around the corner.
I have a feeling that the smart modders will be working early on 1.7 mods. We still don't know when Numeric IDs will be permanently disabled and have to be completely replaced by Named IDs, and 1.7 gives modders a chance to do the conversion at a more leisurely pace than waiting until 1.8 were to be released and finding Numeric IDs were no longer allowed.