I think that there is a flaw in the setup and programming of these radios, Fire and Police should mantain priority over all other users on a trunked radio system, weither it be analog or digital. When a firefighter keys up his radio, His radio should be set up to tell the system that he is priority, there by allowing his call to go through the system. An other agency using the same system should have their radios set to low priority... such as municipalities, bulding inspecters ect...ect. It is tragic that first responders have lost their lives due to flaws in their communications systems, But I think that who ever is in charge of programming these radios should go through comprehensive training, And set the systems up how they should be set up. Rather than just programming all the radios with their proper channels and calling it good.
What you said is very important.
When my former agency dumped P25 on me, I had no idea what I was getting into. There are SO MANY imbedded features in the radio and in the system, even with a conventional system, that if left at the default value will be detrimental. For a popular brand P25 radio, there are about 14 pages worth of parameters that go into each channel and personality. System configurations get equally involved.
There are a number of tweaks that can make digital better. AGC and audio gain is one. A unique unit ID for each radio is another. One that I found extremely important in a law enforcement environment is a "transmit inhibit on proper code detect" which stops people from transmitting over an in-progress transmission. On analog, you get heterodyne and maybe capture. In digital, two different digital signals may be mutually destructive ant nothing is heard. Timing parameters become critical, too. An agency must have a system manager who learns these and optimizes them to suit the needs of the agency - AND to make the equipment simple for the firefighter, EMT, or police officer to operate (i.e., you be good at what you do and let them be good at what they do) and conform to their daily needs, not so hard to work you need an engineering degree to use it. The radio has to be intuitive and the designer/system administrator/programmer have to anticipate how the user will use the radio and make it fit the need... not make the user change how they do things to fit the limitations of the radio or system.
Default settings often have hellacious results. For example, when the system was handed over, about 350 subscriber units (mobile and portables) had 6 channels programmed into them and each radio was set for a unit ID of "1." The gain settings were such that keying a radio picked up conversations in the room as well as the officer speaking into the microphone (no, it's NOT a good thing). Simple changes didn't fix all of the problems, but made a pretty significant difference.
As for provisioning priorities, modern systems have multiple levels of priority access, often putting a unit with an emergency button press at the top of queue. Got to be careful with preemption of in-progress transmissions. Fleet mapping and good system administration go a long way to making a system efficient. Message trunking (the system hangs for a few seconds while people speak) is least efficient and must wait for the conversation to time out before that talkpath is reused. Transmission trunking (the system frees up the talkpath after the transmitting party unkeys) is the most efficient. Sadly, a marketing technique to up-size systems depends on setting everything to message trunking and having users complain about system busies ("bonking out"), then requiring the addition of more talkpath channels (which may not be available).
All of these things and more have to be considered before someone can say a system or a particular technology is "no good." Some of it can be made much better and more reliable with optimization. And, some of it cannot. The more complicated things become, the more we have to be aware of techniques at our disposal and the less we can rely on the old fashioned "set and forget."