Running Linux Mint 17 here, finally got everything running more or less. Only when I fire up DiabloIII.exe POL error - stating nothing but that it encountered an error. :) And then battle.net fires up, and everything runs as expected. I just had to use "echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope" to get past the connection issues - and I'm game. Now I just need to fix my horrid fps.
From what I've read online, -setarch has become obsolete, but it used to fix some of the issues you're encountering.
Hmk currently - I've borked it. Installed AMD drivers for my HD6870. Maxed out the settings there. And poof got into the game and everything's all red-ish. Great! Also noticed that there's not a single chatwindow working, also player profiles are not loading.
Hard to believe that no one else is trying to get this running via POL.