I have yet to see anything I could use Dynamo for on the MEP side of things (other than maybe extracting info to Excel).
I'm in MEP side and I can see lots of benefits, anything repetitive can be done with Dynamo.
We are currently looking at
Copy/Monitoring Levels
Creating views with added templates
Creating Sheets
Creating Worksets
Creating Spaces from Rooms
Schedules
Also I've used it to copy parameters from a linked architects model to an excel sheet, then copied that sheet back into our model, but populating our shared parameter information.
What I'm aiming for is a set of Dynamo scripts which can set up a project for us, quickly. all our standards in place by running a few scripts sounds good to me.