The paper I discussed earlier also mentioned some potential problems with deliberative democracy:

• Citizens can deliberate to make a decision, but can they monitor its implementation? You could argue that representative democracy also suffers from this issue, because the sensationalist press doesn’t help voters hold their representatives to task. But I agree with Kim Campbell: you’re not voting for a set of policies to implement, you’re voting for someone who will think on their feet.
• What about the use of power (eg: class differences) within deliberation? Who has time to show up to deliberative sessions? Who knows how to be convincing in those sessions?
• Can The Powers That Be set up deliberation to skew the results? For example, by the time it came to make a recommendation, the BC Citizen’s Assembly on Electoral Reform were no longer lay citizens, they had been educated up to being experts on electoral systems.
• Will a few people with a lot to gain or lose overpower many people who have less direct interest? Not-In-My-BackYardism is the most well-known style of this.
• If deliberation is done on a local level, how do you deal with larger geographic issues? This is a huge problem in representative democracy, that proportional representation doesn’t do much to solve. Liquid democracy is the only solution I’ve ever heard of…
• Aren’t most people (except the NIMBYs) too apathetic for this to work?