I think some organs would sound badass. Church organ wouldn't be my first choice, mostly because i dont think its something that would blend well in their scheme of music and hammond organs are used by everyone and their mother. Perhaps a reed organ would be nice, richer sound. I kinda wonder if Mike would have had more organ or synth/keyboard in the music previously, but just didn't really have the ability/means to use it. A retarded dead squirrel can play all the piano opeth uses previous to Damnation (except silhouette), so I I wonder if Mike would have wanted more but just couldn't write or play it.