It's been said before, but since it hasen't changed and I am of the opinion that this is really important, I'm bringing it up again: the prone condition is broken.
During my turn when I am prone or fall prone, I should be able to use half of my movement to stand up again. As it stands, not only am I not able to actively stand up from prone, my turn is immediately skipped when I fall prone, even if I still have an action and/or bonus actions that I can use. Please, please, change this according to D&D 5e rules.
Even worse, in most cases when you knock an enemy prone, they stand up even when it isn't their turn so you don't get any of the benefits of the prone condition. Also, the barbarian eagle heart attack indicates that it applies the prone condition for 2 turns but the enemy immediately stands during their turn.