Honour, Hope, Love
The way Classes are set up are... weird for now. I'm just going to state some opinions
1) Tier 1 Classes should stay true to their initial design and only be used until Level 30-40.
2) Some Tier 2 Classes are fairly unique. Ninja, Pirate, Berserker, Wizard and Dragonslayer are generally 'standard' Classes for most MMOs. Allowing them to scale up to 150, similarly to how Subraces currently work, would allow for varied uses. However, there are a ton of balance issues to work out. Berserker needs a damage cap of some kind. Dragonslayer's Elemental Defences are a problem to deal with, setting it up to follow the Elemental Wheel and triggering on the Base Element of the Dragon might work? It's... difficult to balance.
3) Personally, I'm hoping that future Class updates treat Classes like Subraces, allowing the Class Armour to take the use of the Subrace slot, but only allowing HUMANS to upscale to 150. Currently, there is no benefit to being a plain, vanilla human except for very select fights. This is going to sound weirdly racist, but HUMANS NEED LOVE.
I'm hoping for Paladin, personally. The War was won by Paladins, and Sweeping Paladin would be an excellent start.