Planner absolutely must have structured tags - Tags that once used once, are available to reuse in the future.
The lack of this feature is one of the only things stopping our team from moving over from Asana.
Agreed. Asana does this very well. For example, I might have a task that is relevant to various projects so it might have a tag to include it for discussion in the next team meeting, one to tag it as a business development task, one to tag it as an urgent task and one to tag it as relating to a particular block of customers. I then need to be able to search all tasks by tag - eg look for all tasks to be discussed at the next team meeting to create an agenda.