Vladimir really needs more counterplay in late game team fights
The particular issue being how trivial it is for him to safely proc Phase Rush on the front lines, and then barrel into the back lines at 700+ movement speed while basically dumpstering 70% of the carries' health without them being able to retaliate in any way, and forcing them out of the fight as the rest of his team kills their front lines.
As it stands, you basically just lose if Vladimir hits 3-4 items. His survivability and damage are both way too high, especially when you compare him to champions like Kennen, who are supposed to excel at team fights. He completely shits on them in both categories.