On a more serious note, I understand the frustration with the notifications being buried under the usermenu, although personally my biggest issue with it is how far the mouse has to travel and the several other menu items surrounding the correct item, causing unnecessary cognitive load.
The fact is however that there are - currently - three different kinds of notifications and not all of them are typically equally as common. I believe it makes sense to group these notifications under one clean menu with only a few items rather than make a separate top-level icon for each of them, especially because friend requests and PMs don't seem to be nearly as common as mentions (maybe other people have a different experience, but I have doubts that anyone gets all three equally often). Things would get even dicier if we decide we need another notification category.
At any rate, the cognitive load and mouse travel time and distance are both clearly lessened compared to the current menu, even when technically speaking opening the mentions in the same tab still requires two mouse clicks. At least it's better than on mobile where you need three taps.