Yeah, I just read an interview with Nornagest saying to that effect. That is weird that Sabathan allowed them to kick him out of the band since he helped found it. I guess he didn't feel that taking any kind of legal would be worth it or perhaps he wanted to leave the band anyways or something.
How could Nornagest kick Sabathan out of the band, Sabathan is one of the founding members. It'd be like when Gaahl and King tried to kick Infernus out of Gorgoroth.
Did he even leave the band because of arguments, or did he just run out of motivation or time? Also, it would fucking suck for Nornagest if Sabathan came back... Nornagest's arms are fucked up, so he can't play guitar any more (not much anyway.)