Our worksets are really basic and is intended this way.
Duct, Pipe, Buildersworks, Risers, MEP Links, Architectural and Structural Links. are all the default ones.
Duct and Pipe is divided to separate the duct MEP Hangers from the Pipe.
Revit is usually good for up to 50,000 elements. Anything more than that you should consider splitting up the model.
Detailing work usually requires all MEP links to be switched off, this speeds up the process on areas that dont need coordinating and performance is the primary driver for our worksets.
If point clouds are being used, they will go onto their own workset, and users make sure this is closed when not in use.
Yes we use the specify option, opening a new model for the first time I would suggest closing all worksets and then open or close what you don't use to speed up the performance as mentioned earlier.