I kind of get the impression that some of the lessons of Miami are starting to get lost again...
True.
One of those important lessons was that it is incredibly difficult for the average LEO to reload a revolver quickly under stress, while being shot it, after having been shot, and/or while trying to move to cover.
Another lesson was that the results on the target/qualification range are not the same as during the gunfight. The offender moves and takes action against you, which the paper/cardboard scoring target does not. One poster here mentioned the high number of shots fired in relation to hits, as evidence of some lack of marksmanship. While this might be true in some cases, the reality is that it is difficult to hit - and instantly incapacitate - a determined offender under the circumstances of a gunfight, esp such as Miami in which there were cover/barriers and concealment and sun glare issues.
The FBI standard of firearms training was and is well above that of the average US LEO, yet the revolver proved to be a poor choice of weapon for the Miami encounter, all things considered. Limited ammunition capacity in the weapon and reloads, difficult to fire rapidly with accuracy, and difficult to reload under stress. Yet as has been noted, even with the limitation of their weapons and circumstances, the murderous offenders were ultimately stopped, at a cost of many agents severely wounded or killed.
Today's offender is better armed, and better trained (yes they practice), and his choice of weapon is not the 6-shot .32 of old, but the high-capacity .40 Glock or similar pistol, in addition to high-capacity semi-auto carbines, and shotguns. The revolver armed LEO is out gunned, fatally.
The high-capacity pistol gives you more chances to hit and incapacitate under street circumstances. Six is often not enough, even for the marksman. The pistol also fires faster, reloads faster (and can be done while moving), and is adequately accurate and powerful for the task.
It is all well and good to talk about "bringing handguns to a rifle fight", but that is not the reality of policing in America. The rifle/carbine/shotgun does not lend itself to the everyday work of policing, and I hope America never becomes a place where it does. The shoulder weapons that are available are useful, but the handgun is the weapon of the now and immediate, and usually the only weapon available when the LEO must deal with the typical reactive - as opposed to planned - threat.
Although I started with a .357 revolver, I would absolutely not choose a revolver as a duty weapon in this day and age. Off-duty, or as a civilian, it could be a wise choice. But not for duty.