This is an interesting to consider since Rashad has asked for a rematch.
In retrospect this question may sound silly. But try to remove the memory of their fight from your mind...
Machida has a special fighting style. However, he seems to fight at his worst against guys that can pressure him against the cage and limit his movement. Like by covering space and staying active on the feet while not giving counters. I imagine Rashad can to this with active footwork and his good reach.
Even Tito Ortiz was succesful in doing this. Machida's natural response to this is the knee to the plexus. Against a fast wrestler like Rashad that could land him on his back.
Also consider the fact that there's more tape on Machida (losing), which can help develop a good game-plan.
inb4shadface
tl;dr: Forget their first fight and imagine if they fought now, would you consider Rashad a bad match-up for Machida?