User blog comment:Commander Marko/Bosh, The Field Medic/@comment-7494532-20130523084146

Combat Rush is extremely overpowered. Taking into account that you should be hitting 40% CDR anyways, a 13s cooldown is really only 7.8 seconds. Then it reduces itself by another 4s? That means you remove 4s off every other champion's ability every 4s. This can be extremely powerful in combination with the champions that have passive reduction anyways. Like Ezreal. Ezreal's ult is on an 80s cd. Now lets say that ezreal takes advantage of Bosh's Combat Rush and doesn't build any cdr. Ezreal can fire two mystic shots consecutively because of its 4s cooldown (which combat rush will nullify). He can do this every 4 seconds. So every four seconds, thats 6seconds being removed from his other spells. That means he can flux every 3 seconds, shift every 4 seconds, and ult every 32 seconds. You want that powerful ult flying in your face every 32s? (Between the 4s wait and the 6s cooldown from Q and Combat rush - he loses 10s off his ult's cd every 4s.) BUT WAIT. Ezreal can get 10%+ CDR with the right items. That gives him a 72s ult that will (with combat rush) be up again every 27 seconds. No. Just no. Zilean's instant CDR is 10s just for himself, and it doesn't effect the CDR spell itself. To balance this, consider maybe lowering CD on all allies by 1.5/21.75/2/2.25/2.5s and increasing their movement speed by 5/6.25/7.5/8.75/10% instead? This would not effect the CD of Combat Rush, although Bosh would also get the movement speed bonus.