As always, it's a matter of which Cirstea turns up. Wickmayer's recent form has been quite bad, the win against Lisicki, who hadn't played for some time due to injury, was in round 1 of the USO. She followed this up with a r 2 loss to Tatishvili 6-7 6-1 6-2. Consistency is her biggest problem, and not just from game to game.
I agree Petra needs to take the initiative and apply pressure, this is the key if Sorana starts off playing well.
I think it matters more which Petra shows up, Tokyo or Beijing Petra.
These both players are so up and down that you never know, but of course Cirstea is clear favorite, her ranking tells why.
If Petra can play really well then it doesn't matter how Cirstea plays, it would be ok no matter how it would end.