As a Scrum Master and/or PM I want to be able to get easy access to filtering the Board backlog (Plan view) to fast and easily being able to drill down the options.

Possible alternative solutions:

• Being able to mark some quick filters as "Planning filters" which does not make sense on the Work view
• Get access to doing custom filtering like JIRA's search view within the Plan view

Personally I would prefer second option as the needs for filtering always change depending on context and adding Quick filters in the middle of planning is not efficient.