If there was all these solar problems why would Dish customers not be seeing a lot of these problem as 61.5? The Dishnetwork satellite operates at less than half the signal strength of VOOM's satellite.
These problems sound more like compression hardware on the ground. They are trying to squeeze all these channels in, and are probabably trying to balance the transponder load. All the channels changing to 720p vs 1080i points to this. 720p compresses a *lot* better than 1080i.
Remember VOOM is doing something that DIRECTV and Dishnetwork have not done before. With all this HDTV and so few transponders, they need state of the art equipment to combine the channels and balance compression as needed. This is pretty new stuff, and the hardware on the ground is probably very untested and needs a lot of work. As they add more channels they probably have to tighten up any slack that they might have. They still have more promised HDTV to come.
They are probably staying up late working with their vendors trying to get the compression hardware bugs fixed.