In reply to Norbert:
Norbet,
i am in a similar situation and i agree with your assessment. I am using abstraction sequencers to completely decouple my random stimulus generation from my UVC sequencer and driver.
I need to create coverage metrics on the data that i am sending to the driver, not the coverage on the data pins themselves.
To sign off a required i need to know that my randomisation has covered the entire range of values. If not then i need to change my constraints or run the same tests for longer, but ii need those numbers out from the sequence.
In my case i intend to create a uvm_sequencer and sample data at the abstraction sequencer level.