I was rather disappointed with Rachel's characterisation in WCP, as well as Ginger Lynne Allen's peformance -- it was much too abrasive and I seem to recall the makeup being freakishly overdone -- it was like she'd been dipped into a barrel of orange paint and then lightly glazed!
Perhaps it was due to the lighting and fairly heavy video compression, but in WC3 her peformance was much better IMO and notwithstanding her background in the adult entertainment industry (of which I was unaware when I first played WC3), the Rachel character came across as quite natural. Having just read End Run for the first time last week, her (Allen's) performance in WC3 seems to be fairly analogous to how I would expect the live-action transition of the Sparks character, were it to ever occur.
Cheers,
BrynS