It might give E* deeper pockets, but that doesn't mean making a huge bid makes any business sense for E*, given their segment of the market. D*'s current bid was viewed by almost everyone as being too high and rumors persist that they are losing money on it - although one would need to evaluate the entire strategy to know one way or the other.
It will be interesting to watch what AT&T might do with a DBS company. But so far they haven't been all that aggressive with their channel offerings via U-verse. They are offering more HD channels than most cable providers, but trail both D* and E* on that front.
As to NFL:ST being exclusive to D* beginning in 2008, it has been exclusive since 2006, when their current contract went into effect.