Guys, thanks for all the replies. Here is the current situation:
-First step (wasted money?) was a new wiper motor, which as I stated above, didn't fix the problem.
-Today I removed the plastic cover, cleaned off what little of the old grease was left, and lube all the moving parts with expensive, synthetic, waterproof grease. This did NOT fix the problem
The wiper is still slow, seems to stick as it moves through it's travel and the wiper stalk on the column still gets hot.
What next? This 1996 C280 only has 118km (73k miles) and I am using a Bosch blade insert.