I don't think you are a nut. This is a pet peeve issue for a lot of people. The technology has been available for a long time, but the baseball establishment has been resistant to implementing and expanding instant replay precisely for many of the reasons that you have raised. They certainly are taking into consideration the good of the game. If they thought that there would be no negative implications, they would have already expanded replay and had balls and strikes called by a machine.
I personally I would rather have every call be correct, but look at other sports. The officiating of basketball is horrendous. In football, you could call holding on every play and pass interference or illegal contact on every other play. In boxing if there is no knock out, it comes down to a beauty contest in the words of George Foreman. Some people would like balls and strikes call by technology, and the technology exists to do it very accurately. In addition to the counter arguments that you have set forth, what happens if the technology goes down in a big game? The umpire would have to call the balls and strikes the old fashion way, how reliable would he be if he hasn't called balls and strikes in 5 years? It would be like asking kids to do math after using a calculator for their entire lives or navigate using a map after years of depending on GPS. The skill would be lost. If this was such a black and white issue, instant replay would already be in place.