I'm been thinking about this, and I think, perhaps, that this is being stretched too far. Almost all City builders have buildings with area effects, e.g., a police station affects things around it in an area, etc. This is pretty basic to the genre. Most of the time the range of this affect and the depth is not listed, it is trial and error. With the adjacency bonuses we are only extending that logic out a smidgen, and to make up for it, tooltips are included specifying the nature and amount of the bonus.
I really like the adjacency system. I think that it really adds to the game and provides the next level that makes SBR potentially different. I also think that Expansion 2: Arcologies and Multi-Tile Buildings will be awesome. You can take your fisheryx3 + wharf setup and replace it with a huge 7 tile building with a neat graphic and special effects. The effect of your downtown buildings will also be really cool, you can get actual skyscrapers and such. And the graphic would vary, but also depend upon the underlying tiles that then created the building.
Note: Expansion 2: Arcologies and Multi-Tile Buildings is not an official title or product endorsed by Arcen. This is the product of me subtly in brainwashing Chris in a very long con to do things I think are awesome. Plus there are some mantis entries that Chris has responded favorably about this sort of stuff.
Note: This post contains blatant lies, hopes, and dreams. Arcen does not endorse nor not endorse this text. In fact, you might even say, they are completely unaware of this text.