Good news, this feature is partially done. :)
Planner tasks can now be copied to other plans. To copy a task, click on the “…” menu on the task. From there, you can select a different plan to copy the task to.
We are currently testing the new Tasks app internally. We will share an update as soon as it’s available.
Group Calendar is a priority for the team, and the feature team is continuing work on it. You’ll start to see some incremental improvements. We look forward to sharing more details and timeframes soon.