Right now each notification can only be toggled on/off, but for some it would help it they could appear for a set time too.
The Match End notification lasts for 30 whole seconds, probably becaused it reminds people what button combo opens Outplayed in-game to see their recording right away. But now the Dashboard shows us what the hotkeys are, so I'd like to turn the Match End popup down to 5 seconds so I don't have to manually click the X each time. (I'm not being lazy the X is right over the button in overwatch to view your profile so I either wait 30 seconds or risk quitting my team).
Here's my grand vision of it all: