"As long as Tahm isn't sticky he can keep his damage."
So how about getting devoured makes you immune to his stacks for 10 or so seconds? You know so you actually have a window to escape. Right now Tahm is packing Juggernaut levels of single target damage with actual CC to keep him on you. Tank, ADC, APC, it doesn't matter, he will get to you and he kill you.
"We believe Skarner was unhealthy because he was impossible to escape once he got to you."
SLOW: 30 / 40 / 50 / 60 / 70% AN ACQUIRED TASTE: The target is also stunned for 1.5 seconds.