I remember reading how when the U-2 first photographed the Sputnik pad at Baikonur, the US photo-interpreters looked at the giant flame trench and thought that it was for a much bigger rocket. It was actually significantly larger than it needed to be for the R-7. It threw them off a bit until they realized that the Russians had simply over-built it. Looking at these pads, it looks like they've done the same here. That flame trench does not need to be that big for the rocket, unless there's some other factor that I'm unaware of.