Have any of you guys come across this?

I have an 81 W150 and when you turn on the wipers, no matter what speed you put them on, its dreadfully slow. Do you think this is a problem with the delay, since it doesn't delay or the motor?

Check your grounds. Probably help to actually add a ground.

yeah ^, and if that doesn't help, you probably need to rebuild or replace the wiper motor...

Add a ground wire. This happens to almost all of the dodge trucks I've owned.

wiper pivots corrode and slow the whole deal down, until the plastic retainer cups break and they stop.
try pb blaster on the pivots, you may need to pull it apart and soak them and add a grease fitting.

In addition to fixing whatever the issue is, there is one other trick that really helps the wipers in these trucks. If you go one size shorter than stock on the wiper blades it makes a huge difference in performance. They move much faster.

-Jon