It makes sense that empty slots get refilled with something and with both 74w and 79w having a sat moved out, there's two slots for something new. But whether its a ku or c band bird or something else, that would be a question as would be what the current commercial demand is for more tp's is at this point. DTV, DN, Sirius etc. would seem to be fully built out. Have to speculate that there is not enough demand right now for whats in the sky over eastern North America already or else these two birds would not be moving to somewhere else that presumably is more profitable. Then again maybe they are moving so something new with more up to date technology can take their place.
It'll be empty until some satellte operator decides there is enough demand in North America to drift a sat there or launch and operate one there.
Election 2012 should be interesting with those 2 sats gone. Gut feeling thinks a lot of election feeds are going to be horrible skype since you are missing quite a bit of sat capacity to cram news feeds on for that once every 2 years heavy demand night.