So troll-Kalista can throw a squishy ally on top of the enemy assassin?...

Except that. you know, her ally can both choose to accept or decline the bond AND is ultimately responsible for target selection?

In truth, I'd say that a Kalista with a trolly bonded ally is more screwed than the trolly Kalista.

Ally has to agree to be the soulbound.

I just wish they could break the pact at will (and maybe a 3 min cooldown to make a new pact).

Someone didn't read the patch notes. The ALLIED champion gets to decide to death fling themselves. Of course if it's , the only ones who are going to be dying are the enemies.