I think the idea of not entering a "landmark" for parking lots is good (though I have myself been guilty of this), unless it is a parking facility. Landmarking shopping centers helps you get your bearings, in my opinion, where as landmarking a single store adds to alot of clutter.
All in all, I think rather then belaboring the point over and over, someone (thats been around awhile) just needs to come up with a standard, and perhaps run a vote, if a consensus amongst the voters is reached, adopt it as policy and move on until something in the client facilitates a better system. These grey areas make for alot of redundant work and also end up in some people getting messages over conflicting information, and not knowing which way is proper. I know that I'm a much better editor now then I was a few months ago, and still have alot of room for improvement, but in the spirit of offering a solution, this would be my points for consideration:
1. Landmark parking structures, especially in places like urban areas where parking is an issue
2. Landmark shopping centers as the perimeter of the building.
3. No landmarks for single businesses - unless this is a gas station, or commonly used directional landmark, like, in Lethbridge, AB, we have a watertower that has been converted into a restaurant. It sticks up above the skyline and people often use it as a basis for directions. As this is subjective, use your best judgement.
4. For very large landmarks (think airport, disneyworld, etc), mark the area that a person would be driving to -- like, the terminal as opposed to the runway.
5. Landmark schools, parks as they can also provide a visual heads up of reduced speed zones.
One other random observation is that when I use "outsourced" data source results, like yelp, etc, from within waze, it almost never routes me to the proper place - it simply takes me to the "center" of the street where the business is located -- this may be a problem specific to my portion of Canada, I don't know.