Generally a set-up like Cop + Doctor and everyone else vanilla is considered reasonably balanced. All-vanilla and nightless games have also been run and seen a good amount of success for both factions.
Town in this game had:
MrL's lightning rod
Aero's Innocent child
DD's Forensic Investigator
All these roles if played even somewhat smartly are neutral utility AT THE VERY WORST (some of these are extremely strong)
Coroner and Nexus are whatever and Princess is negative utility but unlikely to be enacted.
If asa hid his hammerer, then Mafia had:
2-shot janitor (not useful)
1-shot ninja with a voting restriction (...)
A player with 1-shot immunity to kills, cop investigates (which there were few of), and his teammate's vanillarise (fine)
An odd-day vanillariser that didn't know who his teammates were
Town is SO MUCH stronger than mafia in this set-up compared to the more basic setups. The main thing in mafia's favour is a decently sized team (ignoring third parties it's five mafiosi vs. 13 townies), but town has no reason to have such a dominant advantage at night time.
I think the two games we've hosted with a setup most similar to this is Aero and Ryan's Sun and Moon (landslide victory for town) and Maribro's Users of Qld Smash (town won despite getting outplayed the whole game).
Here's an example set-up from Mafiascum (which checks setups for balance beforehand pretty rigorously) with similar specs to our own and had town win: https://forum.mafiascum.net/viewtopic.php?p=6879738#p6879738
You can see that the town is much weaker and the mafia are much stronger and town still managed to win.
Insie was going to die because even if asa had hid his hammerer powers why would Insie even bring up hammerer in the first place? It's not a role we'd know of beforehand and he's not just going to flick through roles on the Wiki one day and arbitrarily go "hEY GUYS WATCH OUT FOR POTENTIAL HAMMERERS". Hey asa when's the next game.
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