First of all, tank Ekko deserved some more attention, so i want to say that i'm overall quite ok with those changes, i just want to point out some things i don't like so much.
1. The nerf to the Q's base damage is ok, but i will prefer more something like (just an example): 60/70/80/90/100. The point is that they nerfed the base damage by 20, and increased the AP scaling by 10%, but you max Q first, so is a nerf even to the AP Ekko early game because you are not going to have enough AP early/middle to compensate the nerf just with the 10% more AP scaling he is going to get. Nerfing the spell less at lower levels and more at higher levels will remove at least a little bit this problem. ( i know is not SO easy to do this properly )
2. The ult changes are a bit mèh IMO, they removed 50 damage from the ult (that are not the main problem with Ekko tank) and give to it a 150% AP scaling?! This means if an Ekko manage (maybe just for luck, he spam R after being caught to save his own ass after some CC and damages for example) to ult in the middle of the enemy team he is going to...holy moly, the amount of damage is insane! xD The ult is just fine as it is, or at least, the damage part of it.
In conclusion, i like to play Ekko and I prefer him as an AP assassin/fighter then as a tank, so i'm quite happy for those changes anyway, unless for that 150% AP scaling on the ult... this is just so "LEL" for me. xD
Also, I hope you will understand because my English is not so good. :D