Man Tahm Kench's W nerf is gonna be pretty insane
That's a lot of power taken away from his saving. CD is almost twice as long going from 14-10 seconds to 26-14 seconds. It's rank 5 will be as long as his current rank 1. Damagewise is interesting, the AP scaling is going down (although that's not really important) but the base is changing from 20-32% of their health to 31-35% so he gets more burst (particularly early) but a lot less individual uses.
I guess if you want the consistent saving potential you need to max W first now.