I have a suggestion that could help alleviate the hatred against Coroner. Even if there is a Janitor/Disguiser, I still find the role totally useless, and so does most of the community.
Don't remove anything the coroner can already do, just add in a "lookout" type ability, meaning that the Coroner can see all players who visited the deceased person the night he/she died.
Before people start objecting to this, let's consider a few points:
#1 - Coroner would receive this information later than a normal lookout because he has to wait a night for someone to die, then another night to examine the body. This would justify the extra information he would get beyond a normal lookout.
#2 - Some will say this would cause problems for the Janitor, but this might make a Janitor consider not using his ability on the first night, as they typically do. This would also give more motivation for the Mafia to kill the Coroner as a legitimate investigative threat.
Though the Coroner can do more, he technically would not start becoming useful until day 3, which would be significant for evil roles to then start claiming Coroner, adding more variety to the game.