A preliminary inquiry is a check and balance in the system in serious cases. It’s purpose is to have an unbiased judicial determination of whether there is enough evidence to warrant a trial. While it’s true that full disclosure obviates the need in some cases, watching a video of a complainant talking to the police is not nearly the same as being able to discover the case by asking questions of the complainant. Many cases are re-assessed by both sides after a prelim and often result in more realistic views of the strength of the case. But now, prosecutors “are under orders to prefer indictments and to limit preliminary inquiries or to get rid of them completely.” This is what happens when the Crown has more power to determine the process than a Judge has.

Defence involved in murder case says forcing clients to choose between preliminary inquiry and speedy trial is ‘extortion’
Source: Ontario lawyers say clients forced to choose between rights in murder case – The Globe and Mail