I rolled a new orksbane and I'm now sure what his best talent yet is... I'm not sure but tell me what you think
I would go with Corrode 5/5. I don't want to diminish you excitement, but I would not spend too many resources or too much money on Orks. If you play more than a few months, you will likely set him aside for better heroes.
I agree with Bdelley, Corrode is the top talent for Orksbane. You could also make a case for Stoneskin and Bulwark but they are far secondary to Corrode. However, I would consider putting Corrode on SK or DD before Orksbane as they are superior tanks.