Why can't Tahm Kench ult while he has an enemy in his mouth?
This could be such a strong engage tool if this was possible. Eat someone, and then drag them into the middle of your team. I think Tahm Kench should be about more than just devouring allies. He should be able to make big plays while he has an enemy in his mouth, and this would allow him to do that. And don't tell me it doesn't have counterplay, because he has to get 3 stacks before he eats you. He's not like Blitz or Thresh who can just grab/hook you whenever they want.
and use it on yourself to remove the slowing effect and kidnap your target quite a distance.