Because the third expansion has been announced, but no new features have been declared: I wanted to throw an idea or two into the mix for the developers' consideration. To be direct, I believe that it is unlikely that we will be getting another class in the upcoming expansion; I find it far more likely that the tengu will be released as a race before a new class. That being said, here are my two cents on the subject, simply as a thought exercise. I will be using some of the terminology and skill names from the first Guild Wars just to establish some links between the original and the new version of the class.
The Monk is an old class that existed in the original guild wars as a healer class with a small amount of martial arts flair in terms of their appearances and emotes. This is not simply a re-release of the original class though; much of monk's theme was built into the Guardian class. No, I simply propose picking up some of the monk's theme from the first Guild Wars and mixing it in with some of the martial arts themes that Assassin had but thief does not, as well as some of the play style elements that Dervish had. Mix those liberally and add in a little bit of new ideas, and you get what is listed below.
Armor Type: Light or Medium. I'm not saying that they should be able to use both, just that they could fit into either grouping.
Ki is measured in points. Certain weapon skills will allow the monk to gain a ki point (two-handed weapons will have two skills that grant a ki point, while each main hand and off-hand weapon will have a single skill). You may have a maximum of 5 ki points and these points decay down to 0 when not in combat at a similar rate to the warrior's adrenaline mechanic.
You spend Ki points on finishing moves. Activating a finishing move consumes all of your Ki points. These moves are bound on F1 through F4. Each of these is a powerful unarmed strike of some sort. I am not here to design the minutia of each and every move, but the following set of four is an example:
F1: high damage finishing move. No additional effects, but damage scaling on how many Ki points were spent.
F2: control finishing move. A small amount of damage, but inflicts knockdown or launch. Duration/distance determined by Ki points spent.
F3: defensive finishing move. A small amount of damage, but blocks attacks from the target of your attack. Duration of block is determined by Ki points spent.
F4: healing finishing move. Does not deal damage, but instantly heals you based on how many Ki points were spent.
Physical. Monk physical skills focus on mobility, unarmed strikes, and moving your opponent.
Mantra. **Monks have access to mantra skills that fill a wide variety of support effects. Condition removal, boons, healing, and endurance recovery.
**Intonation. Similar in function to a signet or one of the herald's legendary dragon skills. These are elemental-themed abilities (air, earth, fire, water) which can be activated to produce an ongoing effect that enhances the wielder. These effects are never boons, but rather unique minor effects. They can be activated again to produce an elemental spell effect that leaves behind a combo field of the appropriate element.
Orison. These are instantaneous minor magical effects that apply boons in addition to their initial effect.
Combination. These are skills that behave much like chain attacks. Each time a combination skill is activated, it grants 5 seconds to use the next skill in the chain. After the final skill in the chain is used, the 5 second window times out, or one of the attacks is blocked, the skill goes on cooldown. Many combinations have strong ties to conditions.
An example of skill of each type is listed below:
Physical: Scorpion Hook Kick - Leap up to 600 range to your target, deal damage, and pull them 600 range behind you.
Mantra: Mantra of Purity - 2.5 second cast. Meditate, charging a spell that will remove boons and conditions from you when activated. Grant yourself a random boon and condition when this spell fully charges. --> Contemplation of Purity - Instant cast. Remove a boon from yourself and two conditions from yourself and nearby allies; if you removed a boon from yourself, you instead remove four conditions from yourself and nearby allies and grant Resistance (2 secs) to each target. (Holds 2 charges)
Intonation: Chant of Engulfing Embers - Activating this skill makes all of your weapon attacks strike 1 additional target, if that target is within 360 range of your primary target. --> Sweeping Cinders - You strike nearby creatures with an explosion of flames in a 600 range radius that deals damage to up to 6 targets. Leaves behind a Combo Field: Fire in the area for 3 seconds (but does not have any other ongoing effects).
Orison: Draw Conditions - You transfer up to 2 conditions from an ally within 900 range to yourself, then, flip those conditions to boons.
Combination: Lotus Strike - Damage your target and apply chilled (2 secs) to them. --> Renewing Strike - Damage your target. If they are chilled, apply chilled (2 secs) to them and then reduce the cooldown of all of your other skills by 1 second. --> Way of the Lotus - Damage up to 5 enemies within 360 range. Then gain Alacrity (1s) for each foe struck and a Ki point for each chilled foe struck. 15 second cooldown.
Impact -- emphasis on dodging, controlling your opponents and dealing direct damage. Enhances Maces, Spear, and Physical skills.
Martial Arts -- emphasis on conditions, rapid strikes, and counter-control. Enhances Swords and Combination skills.
Prayers -- emphasis on damage mitigation, mobility, and condition removal. Enhances Staff, Trident, and Intonation skills.
Divine Favor -- emphasis on restorative magic, boons, and endurance. Enhances Scepter and Orison skills.
Mysticism -- emphasis on Ki generation, finishing moves, and effects which occur when boons end. Enhances Daggers and Mantra skills.
I am not going into elite specializations as this is more of a brainstorming session as to what the base class could do.
Staff. Power-based melee weapon that quickly prepositions you and has longer than normal range for a melee weapon.
Dagger. Condition damage-based ranged weapon that quickly stacks up bleeding and fury. Some attacks have additional effects if a critical hit is scored.
Mace. Power-based melee weapon that blocks and knocks back foes.
Scepter. Power-based ranged weapon that regenerates allies and grants random boons.
Sword. Condition damage-based melee weapon that attacks rapidly and builds up bleeding, torment, and crippled.
Dagger. Condition damage-based ranged weapon that removes boons from you to deliver powerful point-blank attacks.
Mace. Power-based melee weapon that weakens and dazes enemies. Attacks have additional effects against knocked-down foes.
Scepter. Power-based ranged weapon that attacks enemies in an area and heals allies.
Sword. Condition damage-based melee weapon that grants swiftness and attacks at blinding speed to inflict confusion.
Spear. Power-Condition damage hybrid melee weapon that inflicts conditions while making the attacker hard to pin down.
Trident. Power-Condition damage hybrid ranged weapon that inflicts confusion while granting boons and weakening attackers.
As I mentioned, I kept things rather vague and fairly conceptual, but I am hoping that at least some of these ideas would somehow make it into a new monk class, however unlikely it is. We shall see in the near future I suppose.