Last month, as far as I remember, there was a discussion about the future of Mafia. In general, I received a message from a well-known master, namely Zybr, and I held onto it until the end of the Mafia game, because it's better to focus on one thing: either playing the game or discussing its future. It mainly refers to past Mafia games, without taking into account the latest one, because Zybr isn't even aware of that option yet. But nevertheless, here's what I have:
According to Zybr, Mafia games should be of the following types:

Simple.
Includes the following Factions:

• Town
• Mafia1
• Serial Killer (or without it)

Complex
Divided into two types, namely:

Type A:

• Town
• Mafia1
• Mafia2

Type B:

• Town
• Mafia
• Serial Killer1
• Serial Killer2

Advanced

• Town
• Mafia1
• Mafia2
• Serial Killer

+ Night and Day phases system

In addition, we can highlight a couple of statements that resemble rules or laws:

Law I

The more complex the game structure, the simpler the process should be, for example, clues.
Comment: i.e., if there are many Night and Day phases, then there is no need to complicate the process with open roles, etc. However, this rule has already been tested by ex-Mafia15 in the Scandinavian game.


Law II

It's not always good when all players have Night roles.
Comment:
Mafia is not only played with Night roles. One of the important components is the Day phase, namely discussion and voting.
Explanation: The number of Night roles should be moderate.
For 10 Night roles, there should be 2 Mafia.
As an option, +3-4, taking into account interchangeable Night roles.

Conclusion:
Mafia should not be overly complex. It should be unique and have a vivid atmosphere, and also be colorful in its newspapers.
Also, the best option would be game days lasting 24 hours.