I realize that this may be a big request, but...
I think that instead of tabs on the recent question activity pages, or more likely as a new tab, adding a more advanced filtering option.
For instance, being allowed to exclude tags, filter by accepted answers or not, and, most importantly, being able to combine multiple filters!
E.g.: Filtering posts with tag
AngularJS with no accepted answers and a score >= 0.
I feel like this is a biggish change that, if implemented as a new tab, wouldn't be that hard to implement, but would be very useful.