The list above I made there is only 1 Kind, of how so much Professions can be handled, when you don't want take in so much the good RO System into it and when it should look more like GW's System.
When we would create in GW2 a real well thought out Profession Career System, then everyone would start GW2 first as "no profession".
The Player would start as some sort of "Novice", a normal townsman/woman, which starts as disciple by a Profession Master NPC to learn his/her 1st profession. (Core Profession)
Those Core professions would look like than this:
Warrior
Mage
Thief
Merchant
Archer
Akolyth
This are the 6 absolute most Core Classes, you can imagine, nothing else is more "core", then those 6.
Now, the player could increase in his/her Career by reaching a certail Base Level and by reaching a certain Profession Level
Say for example both levels need to be 10, before the player can rise from his Core Class to an advanced form.
The Warrior for exampple would have now the possibility to choose either the way of the Knight, the Legionaire, the Dualist or the Guardian for example.
When you reach then now for example base/prof level 50, then you receive with your Charactrer the possibility to increase your Carrer level to a Master Class
The Knight could for example now specialize more in a kind of which Knight you want to be > Order Knight, Crusader, Dark Knight
the Legionaire would become a Soldier or more an Army Leader , the Dualist could improve to an Gladiator and so on
There ,the very much kinds of Classes would be all bound on the Core CLass and the player just improves only his Character and rises in his Characters Career over time, with having the possibility, which path of your Career you want to choose.
In Regard of which path you have chosen ,your character receives than naturally different Skills, different Armors, different Weapons and Weapon Types, also different new additional Attributes to the Core Attributes.
I played RO for years, before i changed to GW and I can ever only praise its simple, very easy to understand Character Evolution System, which allows to have lots of different Classes in a game like a Surprise Egg boxed in a 3 in 1 box. A System, that enables the player really to create a class, that you really want to be, because the system will have every imaginable possible Profession as "Career" in it and the player just needs only to create a character and has to choose the right paths of character evolution to become the profession, you want to be.
Some career examples:
Core > Advanced > Master > Elite
Warrior > Knight > Crusader > Paladin
Akolyth > Monk > War Monk > Zaishen Monk (in regard of Shaolin XD)
Mage > Sorcerer(Mesmer) > Wizard > High Wizard
Akolyth > Priest > High Priest > Prophet
Archer > Poacher > Hunter > Sniper
Archer > Scout > Vanguard > Ranger
Thief > Rogue > Grave Robber > Relic Hunter
Thief > Ninja > Shinobi > Assasine
Warrior > Guardian > Samurai > Shogun (Sensei)
Mage > Shaman > Necromancer > Warlock
Mage > Ritualist > Medium > Astralist
Mage > Scholar > Elder > Sage
Merchant > Alchemist > Druid > Creator
Merchant > Blacksmith > Whitesmith > Runesmith
Merchant > Fortune Teller > Visionary > Oracle
Thief > Dancer > Gypsy > Dervish
Thief > Pirate > Corsair > Captain
Warrior > Knight > Dragon Knight > Dragoon
Mage > Animamancer > Demonologist > Occultist
Merchant > Musician > Bard > Minstrel
Warrior > Knight > Order Knight > Guild Lord
Warrior > Knight > Dark Knight > Death Knight
Warrior > Fighter > Dualist > Gladiator
Warrior > Soldier > Legionaire > Army Leader
Merchant > Inventor > Engineer > Mechanist
Thief > Clown > Jester > Harlequin
Thief > Spy > Saboteur > Stalker
Warrior > Executioner > Berserker > War Master
Mage > Cleric > Templar > Saint
Mage > Puppeteer > Doll Master > Psion
Mage > Arcanist > Glyphologist > Runologist
You see, with a career System like this, theres a profession in it for everyones's taste

and they all can base on those 6 Core Classes
PS: Luxon's Siege Cannons are nothing special futuristic, they even look like Cannons from the Middle Age, but Gun Weapons are far too futuristic versus those Siege Weapons, which work with old technology and can only be used with those huge turtles
http://wiki.guildwars.com/images/5/58/Siege_Turtle.jpg
Look at the pickture, how those cannons are bound to the turtles !! with WOOD, only the Cannon itself is out of Iron and the thing shoots with Gun Power, which is in those Barrels ...
Theoretical and for realism, there should be 1 Luxon on that turtle, who puts ever new powder in the cannon, so that the whole thing works ...
Kurzicks have a fantasy weapon, that has nothing to do with technology ,neither with realism.
Do you knw, what technology it needs, to create the small things, that are needed to create a Hand Gun (Pistol), thats imo still far to futuristic ...
GW startet at a inspired from the european Middle Age, at a similar year of 1200+
GW2 plays now 150-250 years later, which means to the similar middle age, that we would be then in the year 1350-1450 ... that are 250 to 150 years still far away from the years, when Guns got invented, so we would theoretically need a GW3 before the game reaches a time age, where Guns could be implemented, when we would take the time age of GW serious and would ignore the fantasy parts of the game, which let it more look like a FF Clone, when Anet makes so further ...