You guys are getting patent prosecution confused with patent litigation. There is a big difference. Patent prosecution (which requires having a science background and passing the patent bar) is not "prosecuting," or suing, people who have violated patents. That is patent litigation. Patent prosecution is "the process of obtaining a patent," and people who do this are called patent attorneys.
there are two different issues. what are reasonable qualifications to become a litigator versus a prosecutor and what are the qualifications to be an EFFECTIVE litigator versus prosecutor.
Just like any judicial matter, the case history is important. In the case of a patent, it first goes through the patent office to a patent grant, and then it may be litigated in the court system afterwards. In addressing the OP question, about what are reasonable qualifications to be an IP attorney, one's concerned about reasonable statistical chance. Just as one could point out that you don't need a philosophy degree to be an effective philosopher (ie: Wittgenstein), the reality is for an average person a philosophy degree improves one's chances immensely. similar to ip requirements Ok, end diversion..
But going back to the case history of a patent that is being litigated, the history doesn't start at the court system, it also comprises office actions during the prosecution stage. This requires at a minimum knowledge of the PTO's procedures, which to a high degree requires studying/passing the patent bar. As mentioned before, this isn't a trivial matter given the pass rate is in the 40% range. And to sit, one needs a science degree. In addition to the science novelty requirements there is a plethora of administrative rules, reflected in the MPEP that determine if a patent is valid. One litigating a patent should also be aware of these as well if they are trying to get a judgement of invalidity. There are also issues of GATT, WTO, and WIPO that is mostly deal with during prosecution that can affect judgements during litigations.
Take a look at the bios of Fish and Richardson: http://www.fr.com/directory/index.cfm?child=directory