In the cinematic "A twist of fate" Annie THROWS Tibbers at a location

I would love an R that only does minor AoE damage in exchange for a significantly buffed Tibbers.

The game needs more pet-based champions.

{quoted}

So why can't this be the same in-game?

Can't have the change without COMPENSATION BUFFS. Annie trades instant cast for more range, more damage, increased AOE radius (on summon or burn), stun/knockback/knockup, or some combination of those things.

She also didn't hit him with it, nor did he get stunned.

Such a noob Annie.