Please let Kalista rebind

I've had two games today where my support up and leaves, both times after dying to the enemy ADC. And both games were the absolute worst I've ever had playing this game. You actually become half of a champion; you lose your HUGE damage proc when your bound partner is gone AND your ult for teamfighting. There goes your hard CC and any possibility of you saving a teammate.

If I were able to rebind with one of my tanks, like Nasus, Hecarim or Rammus, I could have easily made do with what we had. I could turn the game around, I could catch up, and most importantly, I could FEEL useful. Let alone the fact I could have helped Yasuo out even more with having an AoE knockup, or being able to pull one of them out if they caught or things go sour.

Never mind the fact that I automatically lose lane because I can't farm safely without getting 1v3 or 1v4 dove, so I won't be able to stick around and I'm stuck nervously fishing for whatever minions I can get from mid or top until they group and kill us. That happens to pretty much every ADC. But it's worse on Kalista; I actually feel like I'd be better off just going AFK too, because I'm not at a point where I can do anything myself. What's even more annoying is that I can buy a Black Spear in the shop, go up to one of my living teammates, activate it, and it does... nothing. Is this a cruel joke? What's the point of giving me the item to rebind with if I can't rebind?

I'd love to know why Kalista isn't allowed to rebind with someone. I really can't think of a legitimate reason one champ should lose half their kit because someone else left the game.