I have RenaSlam. on ignore so I can't see his post but since danker responded to him I can read it. Anyway, I don't think she is hitting as hard as in 2005 because she isn't as confident. In 2005 she thought she could do no wrong and it showed in her tennis. I think she is much more reserved and tentative in recent times and that is one of the reasons she has fallen in the rankings instead of ascending, as many people thought she would.
Petra Kvitova - Wimbledon (2011, 2014) and YEC (2011) Champion
She's definitely hitting less hard. When she first came on the scene she was hitting more like Seles, now it's more like Bartoli . But it's still a very heavy ball compared to most of the tour, and definitely more consistent.