Sorry dude, you are out to lunch. The level 6 UDKs make teams virtually unbeatable for an evenly powered team. Old accounts will have the champs to beat him, new ones will NOT, unless they are exceptionally lucky. New players have a limited number of champs available, fewer who are built up and even less gear that is required to do it. Even if you can beat these teams it requires an order of magnitude more effort than a team without UDK.
I have been playing for years, my ftp accounts can't kill these UDKs. They can kill the rest of the team, but by the time that is done invariably my damage dealers will be dead as well, and then he can't be killed. Since I also have a level 6 UDK, the opposing team can't beat me either and it becomes a stalemate. And a stalemate means a loss since the only way to end it is to quit out.
My own defence team, with UDK in it, allmost never loses. The only teams that can beat it are ones with team player power at least 50% higher than mine.
There is a wall of these level 6 UDK teams at higher silver 3 and in silver 4. Allmost every team has him in them. There are a few that don't, and unless they have a lot more player power than my team I usually beat those (OP legos can still win though). Typically that involves them wiping the rest of my team except UDK, who doesn't die. Then what happens is either they slowly get whittled down until I win, or a stalemate happens and I quit out.
There is another situation at high levels of arena, especially 3v3, where teams are constructed around a very slow UDK in stoneskin gear. Usually with a defensive single target nuker, such as Mountain King, with the rest of the team made of protectors such as Mithrala and Ursuga, and these fights take a ton of time.
The basic strategy people are using is to make arena fights so rediculously long that people will either not fight them or quit out and take a loss so they can move on. When everyone is doing this it is going to make arena and 3v3 hell and kill that part of the game.