This isn't particularly in terms of layout, but more in terms of keeping people interested in playing the map for extended periods of time, and making your map stand out from many other CTF maps:
The lack of any CTF elements
-Some way to change up the round between each capture is fantastic for keeping people interested. A big dropping point for CTF in many people's eyes is that once you battle through the enemy team's defenses, wipe out a whole sentry nest, escape while the enemy team beats you down and does everything in their power to stop you, what do you have to do? Repeat the exact same task 2 more times. The constant slow, repetitive gameplay can be really boring and frustrating, with no way to end it aside from carry on until you and the enemy team are mentally exhausted.
-For a few more things like this, you should check out
this thread