Personally, I think anyone that goes right into law after getting their technical degree doesn't have enough real world engineering/science experience to really be an expert in that field. That seems to be what technical consultants are for.
I think you need to be intelligent enough to have a gist of what the invention is, be able to find technical articles/textbooks etc. that explain it in better detail, and then be able to pose intelligent questions to the inventor.
I went to law school straight from undergrad. In my experience (I've been prosecuting applications for over four years now), technical expertise is really overrated. Reasons:
1. You usually work on such a variety of applications that it's impossible to have technical experience in many or most of them. I've worked on everything from makeup containers, to fuel cells, to video games, to artificial intelligence for navigating through mazes, etc. Working for three years at IBM or Motorola would not have provided me any technical expertise that would have significantly helped me across the spectrum of these cases, even if it might have helped slightly in any particular one.
2. Most prior art is patent literature. Most patent literature is self-explanatory to a reasonably smart attorney, in part because the literature needs to satisfy the written description, enablement, and best mode provisions. The difference is immediately apparent, once an examiner cites a journal article that assumes that you know everything.
3. The law is often, if not usually, more important than technical details in overcoming rejections. A good understanding of the MPEP and the law on sections 101, 102, 103, and 112 will serve you far better than experience in any particular technology.
4. Arguments that approach even a medium level of technical complexity usually cannot be made by mere attorney argument - they must be made by expert testimony in the form of 132 declarations. Most patent prosecution work is done by large volume filers, like IBM and Sony, and these companies generally want you to leave their inventors alone and obtain patents independently as quickly and cheaply as you can, so expert testimony (at least in my experience) is usually not available from most assignees.
5. Similarly, most examiners are not persons of ordinary skill in the art. As much as 50% of the time, the art is so off, and the rejection is so bogus, that no technical expertise is required to properly traverse it.
6. Remember, the small number of APJs at the BPAI means that only one of them is required to have technical "expertise" in the application on appeal. The other two APJs could have no technical expertise whatsoever. Even the APJ with expertise will usually only have a general expertise, because there are only roughly 100 APJs, and yet hundreds or thousands of art classifications. APJs are mostly patent generalists. As you rise through the levels of appeal, this just becomes more true: most judges on the Federal Circuit are not patent attorneys and have practically no technical expertise, and (to my knowledge) none of the Supreme Court judges do. The same goes for the district court judge that would try an infringement case over your patent, and especially for the jury. If you cannot persuade any of the above non-specialists that you are right, you will lose.
This is just off the top of my head.