As Clint Smith wrote in the January/February 2008, American Handgunner:
"It's alway argued that in a fight shooters will not look at their sights. I strongly agree -- if no one has ever taught them otherwise. To say that people don't, or won't, look at their sights is wrong. People have, they will in the future, and they'll hit the...target too. The correct alignment of the sights is a learnable skill. Is a textbook perfect sight picture available in every fight? Of course not....In fairness, the sights are only part of the issue -- the jerked on trigger doesn't improve anything."
Even when one has been taught to look at the sights, how much has he actually practiced quickly seeing the adequate sight picture and acting reflexively, without conscious thought, on the rough sight picture? As another trainer, Bennie Cooley, once told me, "It's not that I shoot quicker than you do. It's that I see quicker."
With the proper training and practice, it's amazing how fast one can acquire a flash sight picture and hit accurately. Learning those techniques and developing proficiency in the use of those techniques also gives you the flexibility to deal with targets at pretty much any distance. Yes, most gun fights are close range affairs. But what do you do if you've focused all your training on engaging targets 5 to 7 yard away; and the one time you really need to use your gun, it's the one in a hundred case in which you must engage an armed threat 10 to 12 yards away and partially behind cover?
So I suggest keeping the rear sight, and learning and practicing using the sights quickly -- to the extent appropriate under the circumstances, at various distances. If you ever need your gun, you can't know ahead of time how it's going to happen and what you're going to need to be able to do to solve your problem.