Simply put are channelled abilities possible in this game? At the moment there are none and with the way dots work ie global server 3 second tick time are they even possible?

Introducing them for certain classes would deepen the combat system and help make new classes different from the existing ones.

Example of a channelled ability from another mmo

https://www.youtube.com/watch?v=N-A9Eku23hY

Another example of a single target ability that can heal or damage depending on what it is casted on

https://www.youtube.com/watch?v=x4ld3p9CFC8