Alright...let's see...

As far as I can see, I envision your class system to be the kind that upgrades after a certain level. That's why you have Lvl1 classes and Lvl20 classes, right? Also, the setting is mostly fantasy, but with a tighter grip to reality than others.

The first few classes:
--Swordsman: you plan on keeping it to swords only. It would be kind of unique and more, let's say, true to concept to rename it an "Infantry" class or "Soldier" class. That way, swords will not be the only weapon they can choose. And, it makes a more logical progression: they "upgrade" in "ranking"

--Cleric: Fine. Many class systems tie the cleric to the main divine/white magic user. And, it may seem that "Cleric" is often under "Priest". You may want to exchange "Cleric" and "Priest" of sides, and grant Clerics tougher armor and weaponry.

--Mage: A classic. A rename to "Arcanist" would be a refreshing choice, but "Mage" is still fine. "Scholar" may seem odd, but it would also allow the mage class to be considered an educated class, reserved for higher orders.

--Warlock: Well... This one needs some more workout. Apparently, it is a class that bargains with dark entities for power, right? The concept needs more workout, but seems fine. Perhaps if you call it "Bargainer" or "Contracter". It all depends on which is the dark entity you need to bargain with. Fiends? Daemons? Aliens from another dimensions?

--Thief: Ah, the class that thrives upon the grace of others. Seems fine, but it all depends if you want it to be a mere pickpocket or something else. If not, downgrade the Rogue. And make a new secondary choice for it.

--Archer: Well placed choice, to divide the range and melee classes. The problem lies in the upgrades: Beastmaster seems not to be a logical choice. Perhaps Berzerker -> Beastmaster...

--Other choices: Make a sea class, because it has two very distinct and logical progressions: Corsair and Captain. Also, keep in mind the desert region and the region that emulates the Norse. Especially the second option.

...well, I'll be checking the advanced classes later. Not much time. Think about the choices and make the necessary changes, when needed.