I'm reading http://minecraft.gamepedia.com/Server.properties and comparing it with server.properties generated by the server itself.
All options seems to be there, but no matter what I try, the world generated is still "DEFAULT" world.
Tried level-type=SUPERFLAT and level-type=CUSTOMIZED with custom generator-settings, but it makes no difference.
It seems the only settings it takes to heart is the world seed and name.
The wiki states that if you set to Customized, that it will generate default unless you add a "generator-settings" line. The settings and wiki page for that line of the server.properties can be found on the "Customized" page of the wiki.
If you are using Spigot (or whatever other 1.8 mods are out there) then you might want to look into TerrainControl which can help you with custom generation. It will require some setup though!
I'm able to read and I'm able to follow directions. Also, please read the topic title again, I didn't tag it 1.7.10 for you to ignore.
The server.properties file is correctly understood (i.e. settings not getting cleared, like it happens with wrong settings), but nothing works. http://pastebin.com/pzxWy1a3
This is how it looks after multiple server restarts.