You'll turn an ordinary Mafia game into a psychological one if you remove night deaths, newspaper displays, and the like. I doubt HeroesWorld is the place where such things can change anything. It's about the people, not the mechanics. Although I'd love to see how you'd exclude half the players from your 12-14 player games, how they'd argue with you, tell you where to go with your rules that serve the interests of three or four people while the other sixteen don't need them, etc. This might lead to some players leaving, and if someone wants to run a 20-player game, they simply won't have enough people.
By the way, any Mafia game is psychological to some degree. It's just that few people make use of it.
Maybe. But wouldn't that create an imbalance in favor of the Mafia?

Барон "Vampires"
Отдай свои прошлые сны,
В сомненьях себя обрети,
В бешеном танце душа кружится!
Не думай, что будет потом,
Здесь и сейчас мы живем,
Стань хоть на миг сам собой, слышишь!