Darius is perfectly balanced, he will egt tweaks, but only for him to be more teamfriendly, his damage will not be touched ONE BIT, because he is not op; NOT ONE TINSY BIT.
Even I, a guy who played botgames till lvl 30 have not ONCE lost against a Darius in PVP EVER, which is because he is a noobstomper.
Intelligent play and kiting make Darius worthless and he is a detriment to his team as he steals kills from champs who can actually carry, cause Darius cannot even carry a penny over the street.
If his ult did not refresh it would need to do like 1500 true damage to be balanced with full stacks and if it did not have true damage the damage would have to be icnreased to at least the double of the current amount to not make him the weakest and most worthless champ in the whole game.