S1154 cliffnotes - sentence reductions for testimony
S1154 adds 17-25-65, which says that if the state makes a motion within one year of sentencing, the court can reduce a person's sentence for helping to investigate or prosecute another person.
It is now easier for prosecutors to lie to juries about why inmates are testifying for the state at trial. Up to this point, the state would typically keep a charge hanging over a defendant's head until they testified to what the prosecutor wanted them to provided truthful testimony at trial, and then the witness would enter their plea to a reduced charge or a reduced sentence after the trial. At trial, the witness would testify that they were testifying out of the goodness of their heart, and not for any hope of personal gain. Then they are subject to cross examination about the murder charge that they have pending and how they don't really want to spend the rest of their life in jail, which is powerful motivation to take the stand and lie to make the prosecutor happy.
Now, the prosecutor can go ahead and plead their witness to a looong sentence, so that they can testify that they are obviously not getting any help in exchange for their testimony - they've already been sent to prison. Then after the trial the prosecutor can go back and make their motion to reduce the witness' sentence.
It also means that inmates in state prison, not just in the local jail, will be scrambling for information that they can use to try to get a sentence reduction by testifying for the state in pending prosecutions. We have taken a giant leap closer to the federal criminal system, where justice is routinely achieved by coerced/bought testimony from inherently unreliable witnesses who have every motivation to lie. Congratulations.