The problem is that many people believe that mage does no damage and that simply is not true. Some abilities for example vg/fire dots could use more damage, however thats another issue to talk about (one a little more in depth).
The real problem is hat mages suffer from dependable abilities. For example melee have built into their rotation “animation cancelling” of the player they are attacking. So they heavy attack amage for example and they dont do damage (it stops the cast). That prevents the mage from doing damage while that same heavy attack takes away 60-80% of the mages heath.
Heavy attacks need significantly better visual queues (for example some shining effects os that a player can see it coming), but ultimately what really needs to happen is that animation cancelling in any form needs to be removed from the game. This type of gameplay is extremely problematic and abusive in both pve and pvp.
I’d also quickly mention that doing stuff like spamming grit all over is a serious problem and will eventually be self-destruuctive empowering mages once they get the changes they ned to being cc immune and near unstoppable.
What should happen is a dedicated interrupt feature should be added into the game (RMB+LMB) that if it hits a player while they are casting or channelin they are “locked out” of using any abilities for 3 seconds.
This will double over to helping many classes fight healers which are “unkillable” by giving them periods of time where the healer cannot heal providing a balancing mechanic to such issues.
Lastly,
Many spells like Ice spike, Windchill, Pylon need full design passes (reworks). Shifting ice spike into a directed spell similar to fireball, or flamestrike would correct its dependability issue.
Additionally, many abilities, not just on mage, simply need a much shorter animation time. For example half the current time on incinerate.