User blog comment:Emptylord/Blogs/Time-themed abilities/@comment-5514182-20131220064303/@comment-1330314-20131220174502

Actually, I think Rewind is what's limiting Zilean's power the most, along with his global aura passive. It's effectively a very convoluted form of cooldown reduction, and doesn't have any real strategy or subtlety to it (you just blow all of your cooldowns and Rewind to refresh them, over and over again). It's also depriving him of an ability slot for something more useful to his team, such as extra damage or utility, and is forcing all of his damage to his Q, which is unhealthy as it both gives him really low overall damage but an overly strong poke.