The Void Monk

So my friend and I had an idea for a champion and I'd like to hear what you guys think... The basic idea of the champ is a melee monk who using the void and his mind to attack. He would be a tanky, melee, mid damage top laner and maybe jungler. Other than that, his lore doesn't really matter. The idea is low 1v1 kill pressure but good kiting and good focus on carries in team fights. His main gimic is his passive and ult. Currently this may be way unbalanced but I'd still like to hear how people like the idea.

Passive: Every 10 seconds, your next auto attack marks an enemy champion for one ability or 5 seconds. This empowers the next ability that hits this champion.

Q: A short dash followed by a range increase for 3 autos or 6 seconds Empowered: Autoattacks against the marked champion slows by an amount scaling with Q level.

W: Meditates, moving 50% slower for 1 1/2 seconds, taking 30% less damage charging the second part of the ability. When reactived, send a medium distance piercing (minions not champions) skill shot dealing damage, increasing in damage for all damage taken. Empowered: If the marked champion is hit by the beam, a pulse is then sent out of the marked champion, With the pulse dealing half damage Slowing

E: A sheild based on AP with a small over time damage around it. If it is activated again or completely destroyed, all enemies in the field are slowed. Empowered: Marked enemies are stunned instead of slowed

R: Choose a champion to completely copy all of their abilities except for ult for 5 seconds. Scaling switches for each ability to AP if it is AD but is halved. Empowered: Enemy champion is silenced for half of the duration