I thought about it for a second. Seemed decent, then I realised I wouldn't be able to help my friends with crafting or give my wife a minion I came across. Or work together with my fc on melding.
Not every trades in an impersonal way. I'm sorry if that's your experience but I have made crafting friends where we compliment each other. Your pro's are all things you have the option to do alone anyway. The only thing it might help is the RMT. I don't think that's enough to redesign the game, the merchants and even player interaction/UI.
So yea, bad idea. Don't force people to play the way you like to. Forcing people to have to do things they don't want to do won't make them appreciate those things more. Besides that, not everyone complains about that there's not much to do. When they do, what they really mean is that there's not much to do that they like and this won't change that.
BTW, everyone responding should at least acknowledge the OP said to remove all trading with players. So bartering or shard currency etc is out of the question.