More straightforward way to filter
Filtering by role/goal/priority etc. is very powerful, but that power comes at the cost of it not being easy to set those filters. You have to open up the filter dialog, choose from drop-downs and click "Filter tasks". At a minimum this is 3 mouse clicks.
What would be ideal is if the options were presented in the top blue bar. Since text descriptions are liable to become overwhelming pretty quickly, this could take the form of graphical representations e.g. avatars for users, color spheres for roles, icon for quadrant. What I'm visualizing is
where the icons are clickable and apply the corresponding filter.
Even if this is restricted to only one or 2 dimensions (roles, users), this would allow for a much more straightforward way of applying and combining filters.