I just released a script pack that lets you snap the viewport to the nearest side or hotkey the viewcube rotations (never understood why autodesk didn't add hotkeys for it). You can grab the scripts pack here: https://gumroad.com/l/yVVgji https://www.youtube.com/watch?v=RRj9rrWK7Eg
Renamed it to Viewport Navigation Scripts (since it's not purely rotations anymore), added feature for aligning the viewport to selected components, instant/quick rotations, and some other minor tweaks: https://www.youtube.com/watch?v=jKH6yMBUmeg