Did you know post-nerf Tahm Kench...
...still gets over 13450g out of the 5600g spent on Dead Man's Plate and Spirit Visage after level 16, even post nerf? That's without including Dead Man's bonus damage/slow passive value and Spirit visage's passive value which increases his E passive by 20%, which is very effective at mitigating poke. ~53% post-Armor/Magic Resist damage reduction.
His ult, even post nerf (currently on the PBE), still grants him 60 AD and effectively ~90 AP with just those two items after level 16.
A total gold efficiency of 
~3500 + 
~3000 + ~2100 (effective bonus AD) + ~2250 (effective bonus AP) +~2600 (effective bonus health) for a grand total of 13450g, not including any passives outside of the 60 MS from Dead Man's Plate (which was for easy rounding, mostly).
Well over 2x the raw stat gold value from just two items. That's not including the extra value Armor/MR have on him due to his E. Just the health. Spirit Visage is ~120% gold efficient, Dead Man's is ~80% gold efficient, not including passives for either, so no arguing about nit-picking items.
Talk about absurd. I'd go so far as to say these nerfs are too light. You don't even want me to get started on full-build Tahm Kench.
He gets over 2x the gold value most champs can potentially get out of items, which is around 18k at most for the majority of the roster. That's including highly gold-efficient items.
