User blog comment:Lukeatlook/Pyro's Item Overhaul 5 - Supports and the CDR Overload/@comment-5266525-20140719194404/@comment-5266525-20140720010213

I don't think a wide-body change like rewriting CDR should be limited by the fact that it would require large-scale changes. That's the purpose of inter-Season patches - to do sweeping changes and shake things up early enough that it's smoothed out by the time the competitive Season rolls around.

It has happened before, in any case. When the gold efficiencies of several stats were massively changed in Season Three, champion balance was thrown completely out of line and this wasn't even the full extent of changes Riot wanted to do. Removing a few abuse cases initially would be the easy part. I'd say more of the challenge lies in tuning CDR numbers and distribution once the changes' effects could be seen.