As per Kanban, estimations are considered as waste but from the business perspective we need estimation and there is no way to keep features similarly sized. S, M, L sizing does not work as well because executives want to have duration estimates, some variance is acceptable (3 days for example).
At this moment we use task count as buckets of durations: 0 task = less than a day of implementation duration. 1 task = 1-3 man-days of implementation duration. 2 task = 4-6 man-days of implementation duration. 3 task = 7-9 man-days of implementation duration. 4 task = 10-12 man-days of implementation duration. 5 task = 13-15 man-days of implementation duration. 6 task = 16-18 man-days of implementation duration. 7 task = 19-21 man-days of implementation duration. 8 task = 22-24 man-days of implementation duration.
Cycle time is used based on buckets (task counts) and it works fine but I would like to easier the process as much as possible. Is there any suggestion to move towards better and easier estimation techniques?