Guild Wars is one of my favourite MMO-style games for many great reasons. One of these is that the class system does not resemble the cliche "Holy Trinity" of tank, healer and damage classes.
Ravious over at Kill Ten Rats also likes that Guild Wars lacks the Holy Trinity. He'd like to see them get rid of the monk class to further distance themselves from the healing of the Trinity. This would be replaced by the ability for more characters to be self-sufficient, healing themselves.
I agree with this for the most part because, as Ravious points out, any system where you have to spam the chat for a long time looking for one particular class is flawed. However, we can't shaft the monk completely. See, monks feature not only healing skills, but these skills that are dubbed 'Protection'.
Protection skills are cast on players before damage lands, making them a lot more interesting to use than watching 'red bars go up'. Protection skills also often scale in efficiency the more players are attacking the target, making it a direct counter to the mindless PvP tactic of hitting the same fellow over and over until he dies. Suddenly a whole new dynamic is introduced to the game, where players have to judge when the other team is just building towards an alpha strike, or merely applying some pressure. This subtle dance of figuring out what your opponent intends to do is the cornerstone of every decent competitive game.
Other MMO-style games just don't feature these kinds of skills (or if they do, they are on some ridiculous cooldown), and this is why their PvP is regarded as a joke. Protection skills are the pièce de résistance of Guild Wars, they are unique to it and are a massive evolution in competitive gameplay.
There have to be different solutions to the "always need a monk" problem - maybe allow the dual class system to better pick up the slack, or give the other classes a smattering of class-appropriate Protection skills (e.g. Warriors offer protection from attacks). Whatever we do we can get rid of Healing, but Protection has to stay.