I have only been looking to use this in the past couple of weeks and am not a technical expert, but am looking to support my team by streamlining current processes. I was excited when I first stated looking at Planner, after a 1 hour skype induction and then to hear that you can copy a plan. However, on further investigation, I now realise this isn't what we need. What we fundamentally require, is the ability to copy a bucket, within a plan. We are planning to use this to manage a critical path of over 100 actions several times a year and to be able to create a 'template' bucket, that can be copied, would, in fact, be the difference between us deciding to use Planner, or not.
I look forward to hearing if this is something that is likely to happen with Planner in the near future.