Multiple threads on this topic in the past. Lots of strong opinions on both sides. I leave pistol as it shipped from S&W, so mine all have the "feature" in place. I was trained on a 6906 with the magazine disconnect intact so it is 2nd nature to me now.

A search on this forum or google should provide hours and hours of reading.

For concealed carry purposes weapon retention should not be a big issue. No one should know your carrying and hopefully the weapon is drawn as a last resort and retained by the owner.

For LEO or others that open carry, retention is potentially a bigger concern. Plenty of instances of folks losing the pistol to bad guys, sometimes with very bad outcomes. Mag disconnect COULD help if mag release is pushed during a struggle for the pistol.

Even pistols with the mag disconnect intact can be manipulated to fire with mag removed. If the trigger is depressed just slightly to the rear and held there BEFORE the magazine is removed, the pistol can fire a chambered round once that magazine is removed. If the trigger moves forward again without being fired, the mag disconnect will function and the pistol should not fire the chambered round.

Trigger feel is said to be improved on some models with the disconnect removed but I have never compared any side by side. Many folks remove the mag disconnect from Ruger Mark III pistols and report improvement.

Smith and Wesson did offer various models without the mag disconnect directly from factory, usually there is a warning notice engraved on the slide indicating that pistol will fire with magazine removed.

I guess it is personal preference in the end based on use and need.