I would LOVE to see a player market. Some place to either sell or trade for things. Especially soulgems for specific heros.
I have been playing for 2 years and yet I am so far behind on my level and heros I am practically useless in wars and crypts because they are so far beyond what I am capable of. Because the regular market never has what I need.
If games like My Singing Monsters can have a regular AND player market, so too could, and should, Dragon Soul.