I did not get a chance to do arena run. I couldn't even get past the tutorial matches on my craptop.

I made that statement based on having watched a bunch of youtube videos of people doing arena runs. From what I can gather, the draft system hobbles anyone from assembling a really well thought out deck. If you have a basic idea of what your hero can do, and you draw cards to support that, with a willingness to change your plan if you get certain epic or legendary cards on early draws, then you can put together a powerhouse. After that, it comes down to top decking and having the understanding of when to hold back and when to rush.

I saw a video where someone made a deck with 6 Blood Imps in it. This was before they nerfed the blood imps. That deck wrecked simply due to the fact that the draft kept offering a cheap card with stealth that has an excellent recurring ability. There is no rule to cap the number of duplicate cards in a deck in arena, which is my point... If you know the mechanics, you can take advantage and gain a huge edge.