Instead of giving them another free class, i suggest making a guild related class for every tree (Wizard, Swordman, Archer and Cleric).
You know, these guild related classes could also be selected to create a guild, or better, they could be necessary in order to create special guild things, like setting up a stronghold or a church.
Eventually a big enough guild could make a city by combining all the guild related classes?
They are going to add lots of classes, so this thing that I’m saying could already be in their thoughts.
Swordman’s guild class could use defense buffs.
Wizard’s guild class could use crowd control buffs.
Archer’s guild class could use attack buffs.
Cleric’s guild class could use CC resistance buffs or massive heals.