When I had my engine replaced the guys at the shop noticed this same wire was broken and was probably broken for a long time due to the corrosion on it. I never noticed anything with the old engine when turning at lower speeds. Never had a CEL and the engine never stumbled. When the shop replaced the engine the speed sensor was on back order so for the first month, or so, with the new engine I didn't have the sensor and, again, didn't notice anything. The shop installed the sensor once it came in from Isuzu (and yes, it wasn't cheap) and I really didn't notice any difference with it installed.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless