So two parts: how it was set up and how it might be modified in the future. Much of this is pulled from my thoughts in the Spectator Thread, so bear with me in my repetition.
The set-up: First off, the number of people who didn't read and understand the mechanic was...interesting. I'm not sure if folks didn't read or if it was unclear. At any rate, the game premise means two things are true from the get-go: the initial goal is to town-hunt for a Master, and the anonymous nature means conflict is more slow-burning 90% of the time. No pre-existing grudges on the table, no preconceived notions. Players on this site (and in Werewolf overall, really) are primed to find scum upon game start. That's an acrimonious process that upsets the accused and makes folks nervous. Much better environment for Mafia to wade around in versus looking for who's mega-towny. Cabd has other thoughts on how a player list would optimally approach the Master phase, which I'll let him elaborate on, as it's more charisma-based, and that's his wheelhouse versus my logic-driven approaches.
The place where I personally feel the Mafia team really fell down here was a lack of planning and strategizing. They didn't have to be cohesive in the game thread, but there was very little discussion in the PT about whether they wanted to go for a Master upgrade or who would benefit them by getting it on the town side before the game started. Their overall approach to the Master phase, low-posting (which I get as a busy person IRL myself) and low-interest, left them out in the cold in many ways before the first burning votes even started. I realize that night actions went badly for the scum team as well, but a lot of that was a result of the suspicion they'd garnered during the first day phase. Some of it was their own night action choices (not neutralizing the town IC Night Two if not able to go for the kill with both strongman options off the table) but a world where Lancer didn't get investigated and Ruler didn't get Loverized looks very different for Day Three.
Assassin getting the IC designation really fucked the Mafia, as it turns out. Props to petapan: he didn't let it go to his head, he didn't disengage, and he read the game with a seemingly open mind. And they had no plan to deal with it, although Lancer giving him charges wasn't the worst idea. Even here though, feeding his own team given how far behind they were might have been better; YMMV.
Future thoughts on modifying this set-up: I think Mafia might need stronger incentives to go directly for the Master ability. Even though 10:3 with a strong scum team is a scum-sided Mini Game set-up, the allure of four living Mafia is strong. Better power-ups perhaps?
I'm also not sure if changing how the Masterization phase works would alter things (or even if it should). Private voting might allow Mafia to push for their ideal candidate even if it isn't one of them. Delaying Masterization until after the first Day One elimination might work too--make it a thing where a second elim only happens Day One with a town Master. It gives folks more data on where a Master might be useful, but it also increases the likelihood of a divided town.
During the review process this game felt potentially very scum-sided. I know I didn't account for how the anonymous nature and focus on town-hunting versus scum-hunting would change the lay of the land. Any future iterations probably wouldn't have the ability to grant Masterization to other players. The IC designation is clearly strong enough when used correctly.
Elsewhere, mod things I think we'd change with a time machine. We probably should have modified the town sample role PM to include the granting of two more Masters. It made a lot of sense to me, as if scum have the chance for three Master upgrades, so should town, but we erred on the side of not modifying opening post info after the fact, and it did influence the first day phase. For a more detailed breakdown of how it impacted the game from my perspective, see this Spectator Thread post
here for my thoughts. We also erred on the side of having our provided safe claims to Mafia mirror their actual role PMs as closely as possible to reduce the odds of them getting called out for conflicting info, but that made several of them look quite scummy. You can judge for yourselves how in line that was with the fact that several town roles were scummy as hell also. I have a couple other thoughts on how the fake claims were used in some cases, but it factors in enough omniscience that I'm not comfortable ragging on anyone here.