In my opinion the biggest flaw in the new system is how often it feels rewarding.
In the previous system you immediately see your gold go up after a quest or 3 wins.
This feels rewarding and gets you closer to another pack or arena ticket.
The new system rewards you less often.
You get xp for completing a quest..
You see no result from it, until you reach the next level!
And what happens at the end of a season.
Say you are a few 100 xp short of lvl 49.
You will feel cheated.