As commented on by another user in JRA-13151, the 2D portlet behaviour has also changed, in that when displaying issues by assignee, it is no longer possible to click on the user name (the place people tend to click and have since forever) to get all issues assigned to that person. If the user has chosen to show totals (which is totally optional), they could click on the total to get that information, but it is far to the right of the name (and hence not good U.I.). In fact, many times, the name and total won't even be on the same screen due to the need for horizontal scrolling. See my screenshot, attached.

This is even worse than the linked issue, IMO.