Even if the direction of the band was the reason Daniel & Peter left, they'd never say that out of respect for Anders & Bjorn. It's fine. I'm sure it's a combination of the band not being anywhere near its former heights, the change in direction away from metal and missing family. It's also possible he got tired of listening to Christian Joe talk about how amazing God is, and how they should do an album based on hymns he knows from Sunday School.
I've said before, since SOAPF this has basically been the Anders & Bjorn band featuring Daniel, Peter and Niklas. Yes, I know Engelin had some writing credits in Battles it's pretty likely the overall direction and majority composition was by Hipster and Bjorn.