You have to remember, that a military person, who has made it a career, will go on dozens, perhaps hundreds, of deployments as part of their "job". No one has the chest to accommodate the medals you are suggesting.
On the Civilian side, there are Provincial Awards. There are also National Awards, as well. Police, Corrections and Fire Services also have their Awards. All of these are medals. Civilians can also earn UN medals, as you mention later.
Yes. Unfortunately, you are correct there. At the same time, they are getting a 'higher' award that is meeting criteria that lower ranks may not meet.
If you are wondering about the criteria set for Canadian Honours, Medals and Awards, here are a couple Government of Canada links, and you may find that some of your concerns about creating awards, those criteria have already been created:
Canadian military honours and recognition, orders, decorations, medals, insignia, departmental awards and memorials.
www.canada.ca
This chart shows the sequence to wear modern Canadian orders, decorations and medals.
www.canada.ca