Cons: Simplified gameplay. Taking a massive time-consuming game, D&D, and compressing it into an mmo format. The cash shop has a huge impact and casual free to play gamers will not like it. Hardcore and dedicated free to play gamers might be able to stick with it and get enough money to buy things that you normally need to get in the cash shop, but that's true hardcore.
However, you can create your own adventure, the combat is pretty nice, not the best but at least you aren't just smashing keys. Granted, you will only enjoy the game if you want to enjoy it. That's how mmos work.