Currently there is a limited number of work and rest periods available when creating an interval workout. The choice is rather small.
This makes certain workouts (such as kettlebell half pentathlon, certain CrossFit benchmarks etc) either impossible to program correctly or just awkward to run.
It would be better if work / rest periods could be customizable in 5-second intervals for at least 3 minutes. Plus there need to be 6,7,8, and 9 minute work and rest periods too.