Same problem using the 1.0.6 launcher, haven't updated to 1.0.7 yet
If I were to guess why creeperhost is needed, I would wager that it has to do with updating the launcher, and updating the tabs at the top of the launcher. Notice that the "modpacks" tab and the "maps" tab (both of which are in part hosted off of creeperhost) are both unavailable, and I'm betting that when the texture pack tab becomes active that will be unavailable too, in this kind of situation. I would also wager this is an extension of the "no offline mode" pledge. (a feature, not a bug) If you can't contact creeper host then you must not be connected, and if you are not connected then you can't play anyway. Kind of double security just in case someone has a minecraft verification spoof-er?
Also I don't think FTB could really help with the minecraft servers going down, although that was trollishly bad timing.
No, it is the server before the user even gets to login. It is the server that hosts the mods for the modpack and the mpas. If you use vanilla, or some other modpack then you can still get to minecraft to login and play, just not FTB