As I was watching it, I just wondered if it would be more affordable to actually hire an escort/prostitute for a perfect date, or an actual hostage negotiator instead of hiring an active? Perhaps its a conceit of the show, but it just feels convoluted and contrived that people would go through all that much trouble when there are actual people/'experts' already that they could hire.
One premise in the cyberpunk genre is the idea of wealthy individuals and powerful corporations hiring non-persons to commit acts of dubious legality, because non-persons are plausibly deniable.
In most cyberpunk works that use the idea, these non-persons come from a large population of inner-city poor who are denied citizenship by a government that finds it more convenient to simply pretend that they do not exist than to fund comprehensive welfare programs. But the concern that the government would one day strip people of citizenship based solely on their income levels fell away along with the idea that 3D VR would be the most efficient and most common way of interacting with a computer.
Dollhouse provides a more efficient sort of deniability Not only are the Actives non-persons, but they have their memories erased after each engagement, meaning that the details of them are unlikely to ever leak out.
It's a similar concept to Philip K. Dick's Paycheck, though shorter term and possibly less voluntary.
The idea of "meat-puppets" with customized implanted personalities is also somewhat prominent in some cyberpunk works. When you can implant memories and alter personalities, it is logical that it will be used by some to customize individuals, and this can be dehumanizing to various degrees. At it's most benign, some individuals can have themselves implanted with personality traits that they desire. At it's logical extreme you have people kidnapped and modified against their will to be happy compliant slaves, with brothels stocked with people who have been modified both psychologically and surgically to be indistinguishable from popular celebrities being fairly common. Dollhouse doesn't have the surgical modification aspect that makes celebrity impersonation viable, but the idea of having a real experience with the person of your dreams is quite a bit more appealing than a mere financial transaction, even when it is only momentary. Better to hav eloved and lost, they say, to hav enever loved at all.
And there are some other very good reasons for using customized personalities rather than hiring someone off the streets, the most obvious being reliability, the other being speed. Let's say you have an important combat mission. You want to hire a sociopath to lead your team, for one very simple reason, combat units led by sociopaths tend to have hire success rates, higher kill counts, and are less likely to retreat. Putting a remorseless killer with little concern for his own safety in a position where his job is to kill remorselessly with little concern for his own safety inspires the men around him and under him to great acts of heroism themselves. But identifying someone with both the skills and experience to lead a combat unit and the personality traits to do it well without suffering from any crisis of conscience, particularly when engaging in illegal activity, is time consuming and difficult. It is far easier to program someone with that personality and the necessary skills, if the technology to do so exists. Both the Active who was involved in the raid at the end and the one who escaped seem to have been programed with sociopathic personalities for just this reason.
And, although they must use the memories, skills, and personality traits of real people, they mix and match as they see fit to create the best possible individual for the task at hand, rather than simply copying a single person.
I think that a great many complaints, other than those about Dushku's acting, are about genre conventions. It's a genre show. That genre is memory-maniuplation cyberpunk/post-cyberpunk. It isn't exactly a common genre on television, so viewers and reviewers might not be totally familiar with it, but complaining about why rich people would hire a meat-puppet is like complaining about why Riggs and Murtah are still cops after all of their hijinks. It's a genre convention. And the kidnapping mission, it's also a genre convention, as is the prostitution, though it is rare for combat missions and prostitution to be combined.
The question is can Whedon do the genre justice, because it is a heady philosphical genre about exploring the nature of the self that uses violent action adventure as a contextualizing and motivating device, rather than a mere violent action-adventure genre.
Maybe I'm just willing to give it more of the benefit of the doubt because I am familiar with the genre and enjoy it, but it seems that many of the complaints come from a simply dislike or misunderstanding of the genre, which is understandable given that the only real example of it on the screen is Total Recall.
The real way a Memory Machine could make a superstar in any arena would be to keep injecting memories in a person without subtracting anything. A hostage negotiator who had the memories of a hostage taker, now that would be valuable. Or a hooker with the training of a professional acrobat. And a psychotherapist. And a schoolteacher, if you're into the whole Sarah Palin thing. 
There is one profession in which the MindWipe(TM) tech would be a huge asset, and it's a highly paid profession, which would justify the apparently enormous expense.
