That was the purpose of Juggernaut changes. You either have to KS a kill with his ult or you lost the team fight. And ksing with his ult is harder now than before. I would rather have the old darius with a few changes than have this. And with Darius getting some Penta's in Worlds, that just made it even clearer for Riot to nerf the champ.
Its sad that Darius was seen in pro play. Was rarely picked in LCS and was pretty decent and fun. Now it is all about getting 5 stacks. You are also forced to build one damage item otherwise you will get blown up. With the nerf to his Q, which seems to be a fair nerf, it still crippled him. With the nerf to his pull, he is more susceptible to mobile champions and getting kited. Not having 5% movement speed per champion bleeding is another big nerf which got bandaided by
which is still a nerf.
No attack speed reduction and shit damage on his W. Windup time on his Q that shows whether he does his by the hilt or the blade is the biggest nerf ever which makes it high reward when hit and being fked when not hitting it. Ult deals less damage early on until level 11. All of this in exchange of 3 main things. His passive being AD which is still a nerf early on but a buff later on. Synergy with
, and the fact that he can get 5 stacks on other champions even faster IF he can ks a kill or get five stack pain-painstakingly slow.
Shit attack speed and Riot purposely nerfed his attack speed animation, and no it is not because he has less attack speed, it is because riot DID mess up with his animation speed. I have used Darius for too long to know that they did mess it up and i also tested it with the same attack speed.
http://www.surrenderat20.net/2013/01/morellos-thoughts-on-reworking-darius.html
It seems like this was the blue prints to his rework and i can say it did work for a while but he still needs something to be good on his own.