Although I have played this game on and off again since it's last year as WR, I never got to know Zhak. Sure I knew of him, and in game...he never bothered me...on IRC and in the forums he has said plenty that I found offensive...but then again so have many others.
That being said, my vote is to allow him to have his characters back due to him pleading and apologizing...however...if another is banned for the very same reasons...temper/trash talk...then they too should be alllowed to plead and apologize to the community to be unbanned. Otherwise, Yes, you are sending mixed messages to the community, and the worst would be that its ok for the old timers/clicky folks to break the rules and get a second chance...but not for others. Therefore, as long as everyone that is banned for trash talk and tempers is allowed to plead forgiveness...then it's ok for Zhak to come back seeing as most of the replys have been in his favor. If it's not going to be ok for anyone to plead forgiveness due to trash talk/tempers, then no, Zhak/Ponden should remain resting in peace.
Hence, if LuciferBlack wanted to plead forgiveness and agree to not breaking rules on the forums and the community agrees, then he too should be allowed; as should anyone else. Otherwise, if the staff wants to decide alone on bannings for tempers/trash talk; then no...once banned....always banned. This would leave no room for unfairness to come up, IMO.