Iteration is the act of repeating a process with the aim of approaching a desired goal, target or result.
When applied to level-design the workflow looks something like this:
(This is how i work at least)
- Gather feedback related to X*.
- Compile the feedback on subject X* to usable data.
- Use the gathered data/feedback to make X* changes to the map/level.
- Release the updated version.
- Repeat the workflow-cycle until the goal of X* is achieved.
* As an example in this chase
X = competitive multiplayer balance.
Logical the more data you can compile the more successful the iteration(workflow-cycle).
Sadly I'm too busy with my own projects to thoroughly inspect the competitiveness of their works, but they all skilled level-designers that receives feedback on quite reliable basis.
If you send them a message they might can point you in the right direction to one of their more competitive maps that has not been featured in coh2.
ps. Here's a few of my own maps that might in a competitive 1v1.