Ivanovic's peak was really short. Are we considering just peaks or whole careers. Kuznetsova often plays without a brain, but when she was on fire she hit bigger overall than Ana ever did IMO. Have you ever seen Ana hit bigger than this:
Consdering Ana's peak tennis was only mid 2007-mid 2008 and Svetlana's only showed up about 20% of the time throughout her prime of 2004-2009 they probably played about the same amount of peak tennis, with Ana consistently produced over a small time period far more likely to occur the times they played during this period. Anyway I didnt watch all their matches, but maybe Ana was just a bad matchup or someone Kuznetsova developed a mental block against, I dont know, I dont judge how I rate their abilities and power just on their H2H though.
Ana's only real powerful shot is her big forehand. What other weapons or big power shots does she have? Backhand, no, Serve, not really, Net game, LOL! That is the main reason I gave Kuznetsova the edge. She can attack from more shots than Ana can.