Personally, i love that new passive, its a visual change to my gameplay, i actually see the impact its having, especially before lvl 6 ganks, or just at lvl 6, where my lvl 5 jg comes to gank and i level him up just before a massacre (amumu and Vi come to mind). Also, hes never been that hard a champ to use, especially if you learn timing correctly, and even though he only has 1 damage spell, i think the only other support who deals damage close to it is a mantra Karma. Plus no other champion has a game changing ult. (other than kindred, who incidentaly, is the only one who can counter zils ult). And as you said, he has the best Teamfight because of his kit, especially with all the recent changes some champs have been getting. Personally, i would hate to be team stuned in the middle of a Darius focus, while veigar sets up a stun around the team, which means, all round masacres for everyone!!