While I suppose I can, in essence, understand part of how you feel about the immense popularity of having multiple monks in the party, I cannot see why you would want to grant other class more healing options, or "monk abilities."
I was browsing around
www.guildwars.com, and I found this description of the Monk: "The servant of divine spirits, the Monk uses prayer to protect, preserve and restore the well-being of companions."
I did not see any of the other classes having a description remotely resembling this.
This leads me to believe that the Monk's main purpose is to aid their teammates in damage prevention and maintainence of health. Smiting is always, of course, another option for a Monk (one that I find very interesting), but not their primary purpose. Taking this in stock, we realize that the Monk is GW's version of a D&D classic: the Cleric. The Cleric, while not vital for the party's survival in D&D, could make things far easier for them, therefore there would usually be a place at the gaming table for a Cleric who seemed to know what he was doing.
Could a party survive without a Cleric? Yes. Was it nicer to have someone who could heal you or even resurrect if the situation was dire? Yes!
A healing class is a
staple for most RPGs...especially those involving gods! When the game involves gods, it's almost a guarantee that you will run into a healing-type character (the sole exception that comes to mind is Dragonlance, before the Old Gods returned to Krynn).
So, to try to summarize my ideas in a logically fitting sense (and in case you weren't able to much out of the above type), here's what we've established:
Monk = Specially suited to be a Healer/Protecter.
*Cleric = Specially suited to be a Healer/Protecter.
Monk = Cleric.
Cleric is not vital to the success of a party, therefore a Monk is not vital to the success of a GuildWars party. However, like the Cleric, the Monk can make things easier on the party.
Also, in regard to your comment concerning the behavior of Monks, I'm sure that you're aware that there are many, ah,
trolls stalking the various districts of GW. So some Monks are rude? Are they any worse than Warriors who get ticked at the party and stop guarding the casters? How about certain party members who constantly aggro large groups than complain when Healer Monks can't heal them fast enough? There will always be people like that, there is no reason to single out a class. Some Healer Monks, such as me, attempt to do our job to the best of our abilities. I always try to be humble, and respectful to my fellow teammates. Maybe next we should petition to only give certain people the ability to aggro monsters? =P
Well, thanks for reading...and sorry if my point didn't come across to some of you.
*Clerics also handled most undead encounters...however I refrained from bringing this up as Monks were not given the ability to Turn Undead based on their level.
P.S: I leave groups whenever they have 2 Monks already. Also, I always petition to have a Necro and a Mesmer in the party. Just thought I'd get that out in the open.