This is a good question. I think it is necessary to expedite the case flow for a few reasons. First, if a crime has taken place and the case is slow in coming to trial, the people involved will not have closure. More importantly perhaps, immediacy of punishment may deter future crime. In addition to this, to keep someone in prison until trial costs a lot of money. In other words, tax dollars may not be spent wisely. This is an important point to consider in our economic climate.
As to the overcrowding problem, it is acute. We definitely need to do something about our prisons. Some have suggested private companies running prisons. This might not be a bad idea. In this way, we may be able to save some money. Usually private companies are more effective and efficient than the government.