It would be nice if holding down shift would accelerate the viewport WASD camera instead of slowing it down.
There is a feature for instant camera deceleration/acceleration in just about every editor mode, it’s the mouse wheel!
It’s really powerful, even at the highest camera speed, the mouse wheel can take it like 10x faster , or slow it down by quite a lot.
#Editor Preference for Changing Shift
It would be nice though, if we could change the functionality of shift as a hotkey/shortcut via Editor Preferences 
Rama
right mouse button + middle mouse scrolling doesnt change the speed of the cameras movement speed for me, from the dropdown slider thing. Any other shortcuts? Dont want to have to go click on the drop down and then click a point on the slider bar to change the speed and then have to click off to close it.
[Edit] Correction, the number value doesnt change in the slider so there isnt a visual indicator that your speed is changing while holding the right mouse btn and scrolling. But it does work.