Segment adjustments
You can adjust segments of connections for an extra polish when you're finished modeling your diagram with D2.
It's important to remember that these adjustments cannot be synced into D2. There's no way to do so, since the endpoint shapes may move given the structure of the diagram. Therefore, you should not prematurely optimize and adjust segments until the diagram is ready to export/present.
Of course, TALA ideally routes all the connections optimally. Usually only small adjustments will be necessary, if any. Less than a minute. That way, you'll feel free to continue updating D2 code and recompiling down the road without feeling like nontrivial effort was lost.
If you feel like there's segment adjustments that an algorithm should've made for you, please file an issue.