Very good. By doing this yourself, you make yourself think about what happens. And you end up with the diagrams (or verbal descriptions). Writing yourself some kind of notes about a new figure is a good idea.

But (other people have pointed this out) dancing is a LOT more than the steps. The steps are easy (once you remember them). But think about simply walking along a curved path. To turn, you don't twist your moving foot around to the new direction and drag your body behind. You don't do that in dancing, either. But a diagram that just shows the foot positions would not show what you actually do. And even if you are dancing a simple Waltz box, you may be turning. And turning is just one example.

Two things (at least) are more important than the steps:
1) Leading and following. How does the follower know what the leader whats to do next, and how does the leader convey the information? If both of you simply do the steps because you know what comes next, you aren't dancing together, are you?
2) Dancing in the correct style for the dance. If someone couldn't tell from a silent movie whether you are dancing Foxtrot or Tango, you aren't doing either of them right.