Hmm, good point about Mamet. I think Dollhouse, as it currently seems to be structured (mostly one offs, not a whole lot of ties between episodes) would have been a GREAT 80's show premise. For whatever reason, our tolerance (at least mine) for episodic stuff has waned, perhaps because we have been spoiled by great serialized shows or we just demand more of the show structure. I never questioned why Michael and KITT lived in a big truck, why the A-team never seemed to make any money, why Master Ninja wasn't making big bucks as a corporate security guy, or how Airwolf was never tracked back to that mountain base. I probably shouldn't be expecting so much of the Dollhouse structure, just enjoy the episodic nature, and wait for reveals to come as they may.
And to the poster a couple posts up, Eliza does seem to portray a somewhat similar character so far, lots of spunk, a touch giggly, but with a brooklyn-style tough girl attitude. Her negotiator role showed her more serious, but even the glasses didn't really make me think she was someone totally different :P Her acting has gotten better than the Faith days (never watched much of Tru Calling) but I still get the impression she is mostly playing herself. Since she is exec producing, I suspect she is playing to her perceived strengths, hopefully as she gets more comfortable she will try more varied stuff.
The Sierra character acted VERY unlike I expected her to as the gushing fan-girl, but that is probably because her only other real appearance was the non-vocal gunslinger and her voice/accent was not what I was expecting.