That image that broken did looks pretty good. He gives some good advice. One thing you may want to add to the top is a frame for supporting the roof. I doubt that a glass window could support a roof.
I think you may have the displacement map with the wrong depth. I know that sometimes the cement on walls is outside the edge of the bricks but mostly it’s inside if it’s been built correctly.
I’m not sure I would follow that image you have for a lighthouse because it looks a bit unconventional and it looks like that’s what you’re aiming for. I think the traditional lighthouse is like:
You’ll notice what broken was talking about with the blue tint coming from the background. I see that the bricks aren’t quite as visible there but I think the image is very bright whereas your’s isn’t so the bricks are ok but try making a negative displacement.
I don’t like the turret style at the top. I think the flat platform before was more authentic - it looks more like the lighthouse images. Now it looks like a castle.
BTW, if you want to find loads of lighthouse pictures for reference, go to google and hit the images link above the search box and type in lighthouse. I was surprised at all the different types you get.
One last thing, adding some windows and possibly a lamp (physical lamp I mean not a Blender lamp) inside the glass top might help add to the realism.