If you look at those courts that are plagued with court delay, one of the principle factors is discovery disputes. If you look among those courts at those that have an incidence of wrongful convictions, wrongfully withheld discovery is a principal factor. Reform is necessary. 

Darryl K. Brown (University of Virginia School of Law) has posted Discovery Reform in State Criminal Justice (Forthcoming in Academy for Justice: A Report on Scholarship and Criminal Justice Reform (Erik Luna ed., 2017)) on SSRN.

Here is the abstract:

Rules of pretrial evidence disclosure vary widely in state criminal justice systems. In all states discovery is more restricted than it is in civil litigation. In a substantial minority of states, it remains dramatically restricted. That is in part a relic of the common law tradition when it was assumed most cases would be resolved by trial. But trials are now rare; nearly all convictions are the result of a plea bargain. The pretrial stage is the only place in which adversarial process operates and in which parties can evaluate evidence. Most states have adopted broader discovery rules in light of this reality, because disclosure failures have led to wrongful convictions, and because experience show that risks related to certain disclosures are easily managed. The primary agenda for discovery reform in state criminal justice is to convince those states that still adhere to outdated disclosure policies to join the majority of their peers and require more evidence to be exchanged between prosecutors and defense attorneys prior to plea bargaining.