toomanywords

Basically, the character will start of by either choosing a broad range class, between Magic and Nature.
Magic would be mages, necros, healers while nature would be warriors and hunters etc.
After choosing their broad range class, they are spawned in 1 of 2 areas. A magic area or a nature area, where they will choose which class they will go into. Once the class is chosen, the player needs to perform a simple task in order to achieve it (a questline that teaches how to play the game, by making it that way, a tutorial isn't needed).
Once they choose their class, they are sent into the map, and limited to certain areas by powerful enemies (they can still access those areas, however, they will have a -damage% debuff and lower drop rate when in there if they aren't stronger than the enemies).
The map will still be pretty big though to allow them to get things. Hopefully, the map will split into areas with multiple climates, and some are harder to survive in than others. For example, a frozen tundra where you learn ice type moves and can get those subclasses.
In order to obtain those subclasses though, you have to become efficient enough within your class. There will randomly be a subclass artifact that you can obtain when you meet the subclass requirements, enabling you to go on an endeavor to obtain that subclass (questline). A player can hold multiple artifacts at once, but will lose them all when they choose to take a subclass.
Once you get a subclass, it's just like what sono had before, tiers. However, each tier will come with a few skills or abilities or passives that you can choose from. Once you choose it, you can't switch. ex: Solarflare or Sunspot, solar flare gives you more damage when you're under 50% hp while sunspot gives you more fire defense. They could be really diverse but still relate to the subclass. Eventually at like tier 5 or something, you can choose to evolve your subclass. (each tier will become progressively harder to obtain).
When you evolve your subclass, you have to go through a trial. Based on your trial results you get to choose from a few evolved classes (they will still relate to your subclass) ex: normal subclass is Knight, evolved subclass is Knight of Radiance or Abyssal Guard. your evolved subclass choices will be based off of the karma thing. From your evolved subclass, you can choose which initial skills you want, which will eventually effect your last and final class pick. Lets say you go like "Abyssal Guard" and you choose to take a skill like Abyssal Grasp or something, and lets say that the skill allows you to lifesteal in an aoe around you when active. Eventually, when you get to the tier again, your final subclass would have even fewer choices, and will be affected by your karma and previous skills. However, the final subclasses will be really similar, with the differences being changes in a passive or skill.