bear, the nice thing about the ACARS is that a lot of trouble shooting can be set up that you can't trouble shoot or check for in the air. I spent a LOT of years writing up "gripes" in the maintenance office, describing what I was seeing in flight that was wrong. As time went on, I learned how to write a better gripe, and how to do a little trouble shooting, time permitting, before I landed, so I can give the mechanic more info when he enters his trouble shooting tree.
I see ACARS (in its role as maintenance and operations asset) as speeding up that process. If the pilot can add info, I am sure most companies call for them to do so, by voice, as you suggest you would do, and as I did for years.
"Chief, this is 231, we've got the fuel in manual trim. Looks like the normal actuator crapped out again ... " ah, the GE T-58, lovely kit.
