Daron,
We DO use blocks, rather heavily. We are an HVAC Automation company that also installs Commercial Security.
So, we have two different types of dwgs with different standards for each - it had to be that way.
For our HVAC, most of our dwgs are line type dwgs of Air Handlers & etc.. Most of these dwgs are made from many blocks - most of which are brought into the dwg with macros. The HVAC dwgs also have 'panel details', which are a representation of how to wire the different devices to our DDC Controllers. Along with these are Panel points lists, Sequence of Operations & Wiring details - No real need for different layers.
For our Security side, our dwgs are usually floor plans from other companies that we strip out all of the plumbing, HVAC, Electrical, etc.. so that all we have are doors, walls and such. We then place these on a layer called 'floorplan'. We then try to purge out as many layers as we can, so we are left with only our layers.
We don't get updated floor plans very often, but when we do, I just lock / freeze all layers but 'floorplan' then replace the old floor plan with the new one.
I tried using XRefs for the floor plans, on a couple of jobs, but found it was more trouble than it was worth for us. Admittedly, we are used to doing it our way and didn't want to spend a bunch of time restructuring our filepaths & teaching the others how to do it. - Our way works fine for us. (Until I am convinced otherwise).
craigr