The problem is that this decision does not stand alone. Instead, it is accompanied by this:

Holder will also announce that a major suspect in the bombing of the U.S.S. Cole, Abd al-Rahim al-Nashiri, will face justice before a military commission, as will a handful of other detainees to be identified at the same announcement, the official said.

It was not immediately clear where commission-bound detainees like al-Nashiri might be sent, but a military brig in South Carolina has been high on the list of considered sites.

So what we have here is not an announcement that all terrorism suspects are entitled to real trials in a real American court.  Instead, what we have is a multi-tiered justice system, where only certain individuals are entitled to real trials:  namely, those whom the Government is convinced ahead of time it can convict.  Others for whom conviction is less certain will be accorded lesser due process:  put in military commissions, to which most leading Democrats vehemently objected when created under Bush.  Presumably, others still -- those who the Government believes cannot be convicted in either forum, will simply be held indefinitely with no charges, a power the administration recently announced it intends to preserve based on the same theories used by Bush/Cheney to claim that power.

A system of justice which accords you varying levels of due process based on the certainty that you'll get just enough to be convicted isn't a justice system at all.  It's a rigged game of show trials.  This is a point I've been emphasizing since May, when Obama gave his speech in front of the Constitution at the National Archives and explained how there were five different "categories" of terrorism suspects who would be treated differently based on the category into which they fell.