I have to say I really do not like the one in Tsawwassen. There is not a lot of reasonably priced food, most of the year they are not open after 7 pm, and it is not accessible by the foot passengers.
What I really want on the ferries is some decent internet, more charging locations, and alcohol. I would love to have some beers while going through Active pass
The Market on the Vancouver Side is indeed accessible to foot passengers. As soon as you enter from the ticket buying area, there is a doorway to your right. You go through that, and you are on the other side of the fence and you simply walk across the parking lanes and into the market. I only ever go over as a foot passenger and always go into the market if I have time before the sailing. I wouldn't mind a bar on board the main runs. A run up north (the one that goes overnight) serves alcohol.