They’re the most active class in the game by far.
From early game all the way to late game, they have a lot of low to 0 CD skills, which means you always have something fun to press, and you’re rarely waiting around for long CDs. This is balanced this out by having higher SP costs, which also encourages grouping with classes that offer regen like Dievs.
They also adapt much better to the lower spawn rates, since a lot of the high CD skills with large AoEs on other classes is wasted when you’re mostly killing mobs in groups of 1-3 during questing.
The majority of the game is spent constantly moving and killing enemies quickly, rather than sitting in one spot (especially because of low spawnrates), so having lots of moves with high cooldowns is counter-intuitive outside of boss fights/PvP. Leveling a Cleric is very painful/boring early on, for example, because your normal attack is weak and you have very few low CD moves – especially against flying.
I feel like this is the direction IMC should go in with future class updates. Have more fun abilities that we can use often – at a cost – instead of giving us moves that we can only use once a minute or less.