At professional level it is not so much that techniques have changed as mind-sets have - a lot of the best test batsmen score very fast now, but with basically correct cricket shots - cf Warner, Kohli, De Villiers. They have merely recognised through the surfeit of hit and giggle that some balls that would have been left alone thirty years ago can actually be attacked.
Club cricket? Gone downhill quite a bit. Not so much the pitch issue - though the lack of "professional" groundsmen means that there is no longer the pace in club pitches that there once was - but the influence of watching so much hit and giggle stuff. I also wonder if the increase in percentages of guys from an Asian background playing influences this, because they tend to play in a more aggressive, sub-continental manner.