Possible Zilean Gameplay Rework

Hey, while I was trying to sleep last night I tried to figure out a new changed kit for our beloved Chronokeeper, Zilean, since his current kit is kind of boring with things such as a plain stat-giving Passive (that gives a very strange and elusive stat that can't be attained by any other means than having a Zilean on your team or using certain runes) and only one way to do damage which creates unhealthy damage curves. So! Here's my pending idea of a reworked Zilean should look like:

Passive: Chronoshift - When you place a Time Bomb on a ally Champion who dies, they ressurect with % health and mana. Has a cooldown which CANNOT be reduced with Rewind (to prevent that Zil players sits in the base because of huge mana regen to spam Rewind to get Chronoshift back (more on changed Rewind further down the post))

Q: Time Bomb - Pretty much unchanged, the only changes would be that it procs his new passive on ally Champion and maybe some tweaks to mana cost/damage/cd.

W: Open Slot - Yes! I haven't really decided what extra abiltiy he could possibly have here, but I think it would be a wise idea that it at least does damage so we dont get the case with unhealthy damage curves. Would also love if it worked neatly together with some of his other abilites (think Singed's Flip-into-Glue snare that is currently on the PBE).

E: Time Warp - Also pretty much unchanged, was thinking of maybe add some % regen that scales with level on top of the movementspeed bonus? It would fulfill the fantasy of "time heals all wounds" by speeding up time. For use on enemy champions, it could be the opposite, as in giving a decreased regen effect. Just to give the skill something more than just speeding up or slowing down someone's movement speed.

R: Rewind - This is where stuff gets interesting! His Rewind is now his ultimate ability and is accesed from level 1 and can be leveld up 3 additional times, pretty much like Karma, Elise and Jayce. The major thing that has changed is that it has a relatively short cooldown and that the mana cost increases the more you use Rewind (think like Kassadin ultimate) with a buff where you can keep up with how much your next Rewind costs and when it will reset to its base mana cost.

With these changes i hope to make Zilean a more interesting character to play while also preserving that which makes Zilean into 'Zilean', which in my point of view was Time Bombs, Rewinding abilties and of course, can't Killean the Zilean ;)