i'll play along some more as this discussion has remained fairly civil, barring a few obvious trolls.
i think i agree with you on most points.
we need to be careful to parse out exactly what we mean by "the system". so far i've tried to restrict my commentary to address the judicial side of this one particular case. like i said earlier in the thread, i have very serious issues with the increasing militarization of police forces and their propensity to use excessive force against particular subsets of the population (or any part of the population at all, really). but, in my opinion, this isn't a problem with the courts, but a problem with police culture. which, from a practical perspective, is mandated executively and legislatively, not judicially. police forces should be mandated to carry out their stated mission, which is to protect and serve communities, not to wage war against them. the courts have a very narrow range of power though, they can only make decisions based upon the existing law and the existing precedents for how that law is applied, so they're really not the proper avenue to solve this problem.
i do think the grand jury system, while not perfect, works as well as its counterpart in any other legal system, and i would be hard pressed to come up with a more fair alternative. perhaps allowing evidence to be presented by both the defending counsel and the prosecutor would clear up a lot of issues (although you're not "really" allowed to present a defense to a grand jury, in practice you kind of are, as you are allowed to testify before any grand jury that is investigating you. this isn't a right, but is SOP according to the U.S. attorney's handbook).
but grand juries are something we really just have to live with, even if i were to concede for the sake of argument that the system is fundamentally broken, as they're mandated by the constitution (at least in the case of capital, or otherwise "infamous" crimes, which to my knowledge is interpreted to mean felony crimes). i guess theoretically we could amend the constitution to get rid of that provision, but that opens up an even bigger can of worms. first of all its extremely difficult to do, and so from a practical standpoint i don't think it would even be possible. and even if we were able to, i think the process would be inevitably co-opted by partisan politics and we'd end up with something even worse. for better or worse we need to find ways to work within the boundaries of the existing constitution, which means that grand juries are just a fact of life.
essentially i see this as two issues. there's the issue of whether or not darren wilson should have been charged with a crime, and then there is the larger issue that blacks are killed by police in disproportionate numbers. there's no question in my mind that the latter is true and is a huge problem that should be dealt with aggressively. but from what i know about this case, and from what i know about the law (not being an attorney myself), i don't think that darren wilson committed any crime and so i don't think it would have been a good decision to charge him. there are plenty of other cases where officers are exonerated from crimes that they really should have been charged with, i say make an example out of those guys, not darren wilson, who (according to the evidence i'm aware of) was just defending himself. but most importantly we need to pressure our elected executive officers to mandate police forces to adopt a protective, rather than combative, role in communities.