New Caster Carry Stat

tl;dr: New stat of Recast, which has % chance to refund half of cooldown on abilities, to parallel AD carry Crit % stat, and allow for more AP items to exist.

Caster itemization is a bit boring. AD and AP carries have parallels. So, maybe we can spice up AP carry item choice by looking for gaps in the parallels.

AD ~ AP Attack Speed ~ CDR Crit ~ ???

Well, Crit doesn't work on structures, and occasionally doubles (or more) your damage. Having a stat which can randomly crit a spell doesn't work so fantastically, because how do you crit a Damage over Time ability? One check for all ticks? How does that work on Singed Poison trail precisely? One check per tick? That is a lot of checks, and each crit is rather pointless. Law of large numbers plays in real fast, and it becomes just a basic +% Magic Damage.

Besides... loads of spells are about more than the damage dealt. Do we code every spell to have one aspect that is influenced by Crit? Morgana dark binding gets double duration, and her Tormented Soil double coverage area? That would be a serious pain.

But, there is an easy approach. So I propose the new stat of Recast: %chance to have half of cooldown refunded when any ability is cast.

For always on effects, this is meaningless. But that is okay, not ever AD carry benefits consistently from Crit either. But for other abilities, it is universally beneficial. Zoning tool? You can zone twice as well. CC? You can lock down twice as well. Raw Damage? You can do double damage.

It isn't quite as burst as crit, but it maintains the enhanced capacity from a different stat, which opens up more item choices, and it also means enhanced champion/monster interaction, without enhancing building damage output (well, slightly with Lich Bane on some champions)