Lissandra Passive Rework Concept

I took a lot of inspiration from Lissandra's bio which says that she wants to unleash an ice age on the world, her desire for the return of the Watchers and her line upon picking her in champ select, "I will bury the world in ice."

(Passive) Spread the Ice

Feel the Cold - Whenever Lissandra casts an ability this ability leaves behind a trail of 'Black Ice' on the ground for 3/3.75/4.25/5 seconds. Enemies on this trail receive 7.5%/10%/12.5%/15% more damage from Lissandra's abilities. If Lissandra herself is on this trail the gains 10/15/20/25 movement speed as well as 10% damage reduction.

Monument for the Watchers - Lissandra can place a frozen "Monument for the Watchers" on the remains of a destroyed tower. This monument spreads an empowered 'Black Ice' in an area around it that doubles every effect of "Feel the Cold" and regenerates 1% of Lissandra's max mana per second. This Monument remains for 60 seconds and cannot be destroyed in any other way. Furthermore enemy minions inside this area are dealt 10% of their max health per second as magic damage and are slowed by 50%. (180 seconds cooldown)

Her mana costs would probably need some tweeking with a new passive too but I just wanted to post my idea here and leave it at that.

Feel free to leave constructive critique.

[galio-happy]