The reason why this is hard question to answer is because most of the time someone can look at that roster and came up with good combination or ideas, based on his knowledge how things (may) work. He will know what stats have to be put in high priority, he will know the turn order of the team and many, many small things like this that can affect that combination to actually works.
And if he didn't explain those things in depth it probably wouldn't work for you.
Also, no one knows where are you in Arena, where are you in Dungeons, where are you on CB. Can you tell or even show some shots of your team, what is your Arena and CB teams, how are they equipped, what you thing is your weakness based on your observations.
So, how exactly you have your ass served in Arena? You are slow? Your team wasn't equipped properly? You champions didn't work well as team? Give us some ground so we can't step there and discuss how you can improve on that.