I'm not saying that you should make a unique object for every single McDonalds or gas station you see, use one and recycle it. The same McDonalds featured on the (Y) could be used on the (7) and on the (N) as well as every other route that features a McDonalds somewhere along its run.
You should have maybe one or two default project blocks, brownhouse blocks, business store blocks, ect., but alternate and recycle them. Their placement should be prototypical too. In an area where predominantly tall apartment buildings remain, there shouldn't be small brownhouses. That kind of thing. Plus, they should utilize HD textures.
Plus, instead of stretching the blocks one block from the east and west side of the el, it should be two, or there should be some sort of more realistic backdrop. Don't know if this hurts frames, but it would definitely make a difference.