Hello Everyone,
This post is solely based on my views on Hearthstone Arena, you may agree or disagree, it does not matter as Hearthstone is just a game and would not make you a million dollars.
In order to break even in Arena, a player would need at least 3 wins. Any results below 3 would be unfavorable. Over the past year, I have played many rounds of Arena, paying by cash and in game gold. My best result was 10-3 on a brand new account and I average around 3 wins without using bot.
The past week, I have created a few accounts just to test out Hearthranger in Arena. I would have to say that this bot is the best and silver.exe AI is very intelligent. Over the past 20 Arena bot games, my average was 3 wins per round. With the best score of 6-3 and worst score of 0-3.
Even with the best rule set / game play in Arena, you cannot achieve 6 and above average win rate because the cards you draw determine the win / loss outcome. The best Arena round you would ever receive will be, the first free entry and subsequent 2 games after the free one. After that, you will average 3 wins per round.
The best option would be to stay away from Arena, if you average 5 wins / round over 100 Arena rounds then Arena might be for you. It is way better to farm daily quest, 10 gold per 3 winning games than Arena as it would not reward you 10 gold for 3 wins.