I don't quite understand where the fuss about "not trusting IA" is coming from.
Internal Affairs Reports are taken very seriously, as mention probably ten times before. All cases are handled impartially, conclusions go through IA Command, everything is checked over etc.
Yes, the response times are not as fast as you'd think, but our response times have sped up recently, it might not be significantly, but we are trying our best. There are times when an investigation can take maybe less than a few days, and there are occasions where an investigation can take over a week. This all varies with each report.
In conclusion, I find it hypocritical that there are people that complain about officers being unfair and with a Play-to-Win attitude, but they choose not to report it because they don't "trust IA". If you wish for something to happen, then a good start would be reporting it.