There's still a handful of top 10 women Ronda hasn't fought. I don't think Ronda should be forced to move weightclasses just yet. She only defended her title once.
Strikeforce dropped the ball on the division when they let Mann, Davis, Carmouche, Coenen and all the other top 10 BWs go to Invicta. They were probably planning to get rid of the whole division but stopped when they realized they had a golden girl in their ranks. Now they have to get them back somehow or Ronda is left without anyone to fight.