I am one of those who isn't bothered by the lock. In fact, at times I find it convenient. If I am visiting relatives with children, I can lock the gun and then use the cable lock to lock the case. So, instead of one layer of protection, I have two.
I also think the claims that it destroys the lines of the S&W are way way overblown. People should just man up and admit they don't like that hole because of what it symbolizes. Personally, I would have preferred that S&W hadn't caved into the pressure when the lock was implemented but at the time it probably looked like the only way to insure that S&W could remain in business. Fact is, the entire gun industry got a lot of protection from lawsuits in return for Taurus, Ruger, and S&W implementing internal locks.
That only leaves two real issues with the lock. One is that the rotation is in the wrong direction. This can cause the lock hardware to "stand in place" during an extreme rate of muzzle flip and cause it to self activate. Which leads to issue number two. Because of that design, it does present a potential for self activation in the featherweight revolvers when the shooter isn't capable of controlling the muzzle flip. Add in the fact that these featherweights are normally equipped with undersized grips that don't permit good control and you have a problem with self activation that is a fact, not a myth.
However, keeping that in mind, I don't think the lock is an issue for most of the shooting population in any model that weighs in at over 30 ounces and has a full sized grip frame. Only those with very poor hand strength will have a problem with the heavier guns.
I would say to go ahead and get the 686 you want. Personally, I find the 3 inch 686 + a very desirable revolver. Don't have one yet, but it is on my list. As for the lock, if you don't think you'll ever find a need for it, go ahead and just remove it. However, do keep in mind that they are convenient sometimes and in a gun as heavy as the 686 it's only an issue for someone whose hand strength has been degraded by arthritis or injury. BTW, don't worry about losing the key, because as I have discovered on my lock equipped guns, one key fits all.