Ah, the courts. Probably the only arm of the government that everyone has some contact with at some point or another. Sure, some people go to the House, or visit Rideau Hall, and some people even get themselves elected. But sooner or later, everyone ends up talking to a judge about something.
It's amazing, then, that so many myths about judges have persisted. One of the most pernicious is the claim that judges don't "make" law, they "interpret" law. This is deeply confused nonsense. On the one hand, it confuses civil law systems with common law systems. France is the typical example of a civil law system -- there (arguably) judges interpret laws and apply them to particular situations, paying no attention to previous decisions. (I say "arguably" as there is a line of argument in legal scholarship which suggests this is lipstick on a pig -- judges still rely on precedent, they just aren't allowed to admit it.) Canada is a common law system -- and in common law systems, there are three sources of law: statute, convention, and precedent.
Legislatures make statutes. Conventions are made by everyone. Precedent is judge-made law. Precedent requires looking over past decisions -- which, remember, are made by judges -- and figuring out what principles they imply, then using those principles, plus relevant statutes, to make a decision. So, judges make law twice: first when they make a decision, and second when they review past decisions to try to extract principles. No legislature tells them how to do this.
Are courts necessary? Probably, unless the legislature wants to write some really precise statutes. H. L. A. Hart teaches us that we need some sort of institution in a legal system that can determine when laws have been broken and what response is appropriate. Without that, we have no laws -- at best a set of vague social conventions -- and such a system is not stable, tending towards (sometimes serious) conflict.
Courts are not well-designed, though. I suspect -- I'm really not sure -- that our current system emerged from the system of magistrates that existed in England. Magistrates served (and still serve) to apply punishments for criminal violations, and did not (and do not) require formal qualifications. Somewhere along the line, formal qualifications were added -- excepting the justices of the peace and their equivalents -- and the power of the judge expanded to include some of the traditional powers of the monarch. Like Parliament, then, the courts evolved and, like living beings, evolved only well enough not to utterly fail.
We can't do much -- yet -- about the vagaries of biological evolution, but leaving ourselves subject to similar problems for social institutions is a pretty blatant abdication of responsibility.
For minor, routine matters, it makes sense to have a single person yielding a verdict -- as with the justice of the peace, or something like a traffic court. For anything that involves deciding between competing arguments, relying on a single person's views seems like it will lead to trouble. It also pretty blatantly violates principles of self-determination. Putting oneself at the disposal of another when we call him a "king" is obviously anti-democratic and illiberal; but then it should be equally problematic to put oneself at the disposal of another called a "judge". The decision of a group of learned people strikes me as less worrisome, if only because the capriciousness of individual decision is taken out of the equation. Of course, this would have to be a decision rendered by consensus, not by majority vote. (Our system's general fetish for majority votes becomes weirder the longer one looks at it. It's easiest, certainly, but why favour what's easy over what's just?)
It similarly seems problematic that judges are only experts on law. Litigation that requires expert testimony relies on experts called by one or the other attorney -- and, frequently, both who, just as frequently, don't agree with each other. This leaves the judge to decide the case on his or her own opinion, which is pretty obviously unfair. On a related note, lawyers tend to judge arguments based on their persuasiveness, not on their logical rigor or factual merits. Judges are generally no different. This, again, is unfair, as it favours rhetorical flourish over anything else.
The former problem would be easiest to solve, as we could simply allow judges to call their own expert witnesses, who appear to serve the court and neither side of a dispute. One could also institute specialist courts, where one of the judges would be an expert in a relevant field -- say, a physician for a court that heard cases involving medical evidence.
The latter is more difficult. I've thought for a while that being a judge is a sufficiently important job that it shouldn't be left in the hands of the standard sort of lawyer, but someone more broadly educated -- education in law is obviously important, just not only important -- who has received specialized training in determining the fact and law of a case, and in determining the impact of a decision. Some training in better writing wouldn't hurt, either; some judges are great stylists, but many simply can't string a sentence together.
Finally, it's an obvious problem that judges are appointed by single individuals -- the Prime Minister and the Premier (well, officially, the Crown, but we all know how that really goes). I wouldn't want to go the way the US does, and elect judges by popular vote. The problems with importing partisan politics to the judiciary are obvious and well-established; and a judge isn't a representative, but a decision-maker, so popular vote seems inappropriate. A full and secret ballot by Parliament might be an idea, assuming that Parliament were reformed along lines as I recommended previously. Another might be to have judges hired as members of the civil service.
Or we could have a reality show.