How will these changes affect somebody with a plain old RadioShack Pro-95?
You should not have any trouble for now, with one exception. You will notice a drop in volume on those frequencies transmitted in a narrower width. Those of us who have been monitoring federal agencies since 2005, when those agencies began transmitting in narrow band, have been living with the difference between a 12.5 kHz signal and a 25 MHz signal. You have to turn up the volume on the narrow federal signal to hear it and when a wider signal, such as a CHP transmissionl is received you jump out of your chair from the blast. The volume difference can be that pronounced. The newer scanners have an option to program an audio boost for the narrow band frequencies allowing the use of one volume setting for both narrow and wide signals.
The long term problem with older scanners will be when frequencies at a 12.5 kHz spacing are used. The older scanners receive 25 kHz of bandwidth per channel and soon that space will include two allocated frequencies. If a 12.5 kHz frequency immediately adjacent to one you are trying to listen to transmits your receiver will sound similar to the sound of two radios transmitting on the same frequency. If those 12.5 kHz frequencies adjacent to the frequency you want to receive are not licensed and used then it should not be a problem, but when they are you will find your scanner somewhat useless.
When I first began listening to land mobile radio in the late 60's my dial tuned Radio Shack "Patrolman" potable could only narrow its reception range to about 100 kHz, which meant I was receiving many channels at the same time. I didn't have much choice as I didn't have the money to purchase a crystal scanner. I spent much of my time listening to squeals that made me want to throw the radio out the window.
The PSR-600's and a 500 I own can already be tuned to receive at a 6.25 kHz width, which is already the spacing on the 700 MHz band. I've purchased over 20 scanners since the late 60's to keep up with new developments in radio technology. If you're going to play you have to pay!