1.Allow Sheriff and investigator to visit dead people in the graveyard.
Though they are not as useful as coroner but they can go visit dead people to check their roles/alignment
Beside the most simple Excel type role crossing strategy,
I will list a few of the most powerful Coroner play:
1. Evidently Figures Disguiser/informat action
2. Mafia's targets
3. Janitor cleaned Spy/sheriff/investigator/vigilante last will
4. Mason leader's conversion/purge
5. Cultists' possible conversion
6. Witch presence (if last will doesn't match actual actions)
7. Busdriver's night swapping target
...etc etc etc
Those are the strongest reason that coroner is not substitutable in general.
Even if investigative roles are allowed to check dead people, those information listed above are unique for coroner.
2(only if 1 is accepted). hide AFKauto killed person's role in graveyard.
I think this would be fair that no faction gain bonus information from Auto-afk-extra role card flipping.
Some shitsetup would be more fun by afk-auto janitor job.