A few more things that would make like easier:
Make attributes more visible, e.g. https://gramps-project.org/bugs/view.php?id=4970.
Reduce the need for drilling down in other places as well, e.g, https://gramps-project.org/bugs/view.php?id=11950.
Allow sorting on multiple columns https://gramps-project.org/bugs/view.php?id=10656.
Also related to sorting, a minor but annoying issue: Sort order of list and tree views isn't set initially (Bug 12824)
Easier creation of complex filters (maybe already addressed by some of the more recent changes?): https://gramps-project.org/bugs/view.php?id=8651.