Not so much that he was an expert, but he thought he had relevant expertise, made a false presumption about the nature of the law based on that misunderstanding (namely, that because object files would not run without recompilation between the iPhone and instances of prior art produced by Samsung, it didn't count as "real" prior art), and convinced the rest of the jury to deliver a guilty verdict based on whether the processor could execute the same object code or not, not whether the presented evidence actually was sufficient "prior art", meaning a demonstration that the invention was not unique enough at the time to warrant protection, to invalidate Apple's patent.
This seems like an archaic goal that could safely be discarded if the legal system were changed from adversarial to inquisitorial to compensate for the fact that differences in wealth allow the wealthier side to hire more convincing counsel.
Even loser pays can be problematic, though, because the troll or bigcorp can fund a war of attrition for far longer than a startup or small business. I saw a variant of this happen to a company. An adaptation of the inquisitorial system to civil cases seems like the most sensible approach, if the goal is to provide equitable outcomes regardless of the financial resources of the litigants.
An alternative idea is a shared pool of legal funds. Both parties contribute to the pool and the pool is divided equally. If an aggressor wants to hire the best lawyers in the business, they have to provide the equivalent to the defendant.
There is already legislation coming into effect in the US which will give parties 9 months to contest any patent, through the patent office. This should help solve the problem of lay juries deciding the validity of recent patents.
http://ipspotlight.com/2011/09/19/changes-to-u-s-patent-law-...