I think current Darius is top 5 most broken champs I have seen in 5 years of this game.

Ill just name a couple who were way way worse.

1. Beta TF (Most broken in league history)
2. Beta Jax (75 percent dodge chance)
3. Xin Zhao Release- Win Zhao
4. Nasus Release (Ult could do 100 percent max health with 100 ap)
5. Release Zyra (Insane Damage)
6. Release Leblanc (Had to be hotfixed immediately)
7. Early Patch Eve (Insane AP ratios with perma stealth had 0 counterplay)
8. Volibear Release (Go watch youtube videos)
9. Graves Release (Get one shotted)
10. Diana Release (Get One Shotted)
11. Vladimir Release (1.2 second Q's)
12. AP Yi
13. Patch 1.1 Heimer (could have 6 turrets)
14. Season 2 Jungle Alistar (You werent even safe on your own fountain) 15.Release Blitzcrank (Pull was Targeted)

There are tons more op than Darius and iv'e played since day 1 of the beta and played as and vs all of these. Darius is strong but not top 5 ever.