You can always make it more difficult for yourself, for example by not buying any equipment for gold or Crowns. All you can equip are those things that you win in combat. Also, no farming is allowed. Another way to make it tougher is to solo all of the bosses.
Wizard City isn't supposed to be tough. They want new players to get acquainted with the game in a comfortable environment, and that won't happen if things are mega tough in the free area.
All MMORPG's are designed to be easy in the beginning in order to get the players educated on how to play and what will be expected of them in the future. Also, you have to notice the majority of the players are extremely young and may not want to play if it is "too hard" right off the bat. Most of the young players will think that it is too hard and then cause less and less players to join W101.
