This team will not be able to win unless they get a valid pregame strategy going and improve the communication. I play myself in high ELO on the EUW server and nearly everyone is mechanically very good when you reach a certain point.

The dream team has mechanically very good player and are probably better than most other players in the challenger series (except for Scarra, I consider him mechanically weaker than most, but he'd make a great shotcaller).

My point is that the mechanical advantage the dream team might have isn't important enough when weighing it against communication and strategies. When I look at Delta Fox playing I just see a very strong solo queue team with voice chat. The other challenger teams notice this too and this makes Delta Fox very predictable starting in the mid-game.