Professions should be ordinary but with fantastic implementations.
The incentives should be balanced between specialization and generalization.
On one hand, I don’t want the game to be like many RPGs where players are expected to have a character of every class.
On the other hand, I don’t want the game to be like some isometric ARPGs where the only viable builds are extremely focused and don’t allow any room for splashing domains. (Such as how summoning is usually useless unless a build is focusing exclusively on summoning.)