Tahm kench does damage without damage items

I'm not really asking a question when I ask "Is Tahm Kench balanced?". I understand he is melee so it's hard to devour an enemy because you have to get into melee range to get the stacks, but seriously, his whole kit is ridiculous. The base percent hp damage he does on regurgitate is outrageous. You can just go tanky and still do tons of damage which I find really doesn't make sense. Usually when someone goes for an offensive build, the downside is they are squishy. And when someone goes a tanky build, they are tanky but don't deal as much damage. But tahm kench does a lot of damage even without any damage items. In lane, If you focus tahm kench and poke him a lot, most of the damage you do is negated due to the recoverable health he has. So what do you do? Burst him down hard so he can't heal back up right? Wrong, because he can just turn that recoverable health into a huge shield while his adc or team attacks you. So you decide to just ignore tahm kench and focus the adc squishies. You are about to kill the adc and nope! Tahm kench can just eat them, making the adc untargetable, I find it unique and a nice idea, but then it's quite strong compared to something like taric having only one stun to peel his adc. Especially when devouring a teammate isn't even an ultimate spell so the cooldown isn't that long for you to eat your teammate again to save them. It's like I HAVE to play blitzcrank every game in case of a soraka or tahm kench support who have quite a hard time punishing and counter playing.