That is indeed a common problem, more so when working with gradients @magtek. I have to fight that daily with my motion graphics work.
Usually the first things we do to counter that are indeed rendering with higher bits per channel and increasing detail. Next you can add some granular noise on top of everything, at the compositing stage. A tiny bit goes a long way (in After Effects where I normally do that at the end of every project I can sometimes get away with as little as 1%). For some crazy gradients that don’t cooperate very easily you can also layer two separate instances of tiny amounts of noise.
There are also free plugins for that kind of banding and flicker removal if you use any other NLEs: https://digitalanarchy.com/demos/psd_mac.html#d9
Then, as you noticed it: mp4 is the enemy of quality, so if you can get away with it use ProRes or .avi
And last, but not least, as soon as you have the crisper and most beautiful gradients with no banding and upload it to Youtube it will be ruined again (less if you did do all of the other steps). The level of compression they have, and most social channels for that matter, is quite heavy. I’d say Vimeo and Wistia as the best player options for quality, but just remember that none of them are perfect.
