Easily in the last 20-30 years the biggest change beyond the equipment is in one pocket.
While in the past an occasional 8 and out, now it is a common. I can remember the "Chicago Style" one pocket where you lucky if you got a shot every other week.
Ken
One pocket has become much more aggressive at the professional level as new pro's have gotten better at banks and position. They open the rack earlier and play run outs that were unheard of 20 years ago.
It's exciting and includes all the great strategy as before - just at a much higher level. I don't know who first broke the new game open but Tony Chohan is an excellent example of the new style.