it all depends on the type of enemy and situations for a mage to have ground.

Fire, dark, shadow, illusions, wind thunder or gravity they can stand on the ground with the swordman and even more if they are domain type skill. They are the mass destruction in war and they should not least class among the meele class. Mage can be annoying opponents and they have vast uses and even wind mage type can become assasin.

I can write a story where the casting time is a frowned upon thing. I can also make the mages needing more resources to advance or them being difficult to advance and being weak at early stages. It's absolutely in the author's hand to bend. Also most of the mage class need terrain advantages except for magic swordsman. Suppose I am a swordsman who is using wilderness to hide myself now it would be very tough for a mage to catch up to me or find me. They suck at running because of their weak physique only in advance stages do they have the ability to fly.

They are one man army only if they have limitless Mana and protective charm and low level swordsman to protect them.

But if the mage are in the terrains that are fit for them they can become more destructive like if they are in the ocean, volcanic, cold places and dark realms.to swordman bowman and assasin it will place huge burden to their movements and its more disadvantages for them to perform, cause it will consume more energy whats more if they are fighting mobs, because thats where true adventure action truly start. Unless the author place large restrictions on mage abilities. Because the high the level the mage skill the less mana cd. they become slowly terrifying

So overall mage class doesn't deserve to be the least favored class than bowman or assassin, they should be on the scale similar to swordmans popularity. They are good combo if paired in fast leveling

Because Mage class are maliciously targeted by the game creator, it's been repeatedly told in the story

The restrictions on mage are not so severe to the point that their potential in mid or late game will be disregarded. Even though they are slow movement speed and casting speed can be solve by learning training and equiping item. If Mage given time to cast a skill that change terrain or dimebsion suitable for them then chances of wr will increase even they are unable to move for a fraction of second after release they are weak early game they will learn in the future buff, debuff and cc to solve to problem they also complaining that mage are weak in dungeon farming. We might not know maybe they might awaken some real skill that involve time space ice magma gravity arcane or maybe u r nxt song Jin woo to arise but give up early stage what a sad life.