My gunzerker still works. He has maxed skill trees and 90+ weapons in backpack. Only problem I have is backpack being over full (96/27) means I can't retrieve weapons from bank. I tried changing "black market upgrades" from 5 to 40 in the raw tab of gibbed but it didn't help. Looks like I am going to have to split my save into multiple saves.
I have tried to use python recently & it too no longer works... Probably a code change in the game to prevent modders.. Just a matter of time before modders figure out & exploit the code.
Just did a friends game today and it worked just fine for us with all the updates and dlc so maybe its just some people