Failed? I think it's a winner.
To my way of thinking, the Mk23 controls are perfect. I use mine in every mode that is possible, depending upon what I am doing at the time.
The size is roughly equivalent to a 4" revolver and certainly smaller than a six inch revolver while still wringing out the ballistic and other benefits of an non-vented, threaded barrel almost the same length and sight radius as the (disadvantageously) vented, 6" revolver. Holds over twice as many rounds and is lighter than most large frame 44/45 6" revolvers as well.
I bought mine because it is exactly what I wanted. I didn't KNOW it was what I wanted until I went through a lot of money buying (and modifying) carbines and hand guns that without exception fell well short. I wish I had read the Mk23 info before I started down the path years ago. It would have saved me a lot of money in the long experiment that lead me to the Mk23.
The Mk23 does exactly what I want it to. No other pistol available pistol does this in every way I want including the caliber. If the special ops teams prefer something else, it's no skin off my teeth, and I am very happy they had this one designed, tested, and built, and that I have the opportunity to assume they did the work for ME. I appreciate that. Couldn't have afforded to have it done by myself. I'll take advantage and own more or less the same pistol they replaced. The pistol suits me just fine.
From a special ops point of view, can Mk23 really be considered a failure? Or was it another step in the right direction? Time will tell. We'll see (when they want to talk about it) if the replacement pistols are indeed always the better option for them, and we'll see whether or not the Mk23 is revisited some day when the dust clears on the replacements. In the end, I bet they find that it's more than a one pistol world in special ops just as it is out here, and Mk23 or a very close cousin will have a continuing presence even if it's a small one.
I may sell my Mk23 some day or give it to someone worthy. But it will be when my hands can no longer operate it or my eyes can no longer see.
I'm a little tired of the "offensive handgun" moniker. It's as nasty sounding a misrepresentation as "assault rifle" is. From what I read, this was akin to being a bogus nickname intended to fool the brass into thinking it was something markedly different than a "normal" handgun, except with very good accuracy and higher reliability, and so the Mk23 was urgently necessary. This, to assure approval. Accuracy and reliability are nothing new to handguns and change nothing but the engineering and quality standards of the particular service grade product requirements. I'll leave this point at that.