Daleks are not particularly brilliant tacticians, and their strategic goals are no mystery. They are good at blowing things away, it's pretty much their only plan. The Timelords seemed to think sitting behind their technological walls was all they needed to do to hold off the Daleks. That's something they are good at overcoming. Stairs too. But cleverness and guile whips them every time. The Timelord High Council doesn't seem to have a lot of that.