Changing the number of cards to such a low number though, alters the nature of the game significantly.
I placed so much emphasis on the lack of bluffing in the no-look strategy, because that's where most players will be scoring most of their wins, in my opinion. This is because there would be 53 cards in the deck at the start of every game, and the players use up 2 each round, meaning a maximum of 26 rounds.
( I probably should have mentioned it earlier, but in the odd case where the joker is the last card in the deck, then the game is a draw. A 53 card deck is necessary, so that no player can be trapped in an unwinnable scenario in the last round. )
The way I imagine it, there is quite a lot psychological pressure in addition to the need to hide and give tells. Depending on the Joker's starting position in the deck, there can be 10, 15, or 20 rounds of "Town. Town. New round" before the game is decided. That's a lot of rounds of not looking at your card and hoping things will go alright.
This is because what I said earlier, the fact that a player facing a 'no-look' player will never call mafia, is not true. There's an odd chance of him calling mafia as the number of cards in the deck decrease, and his chances of making a successful call increase with each round.
Plus, that's 10-20 rounds of a normal player throwing feints and maneuvers to try to get a no-look player to guess wrongly.
Though I don't really understand when you said:
To be fair, the same could be said of you. If your opponent never guesses Mafia, you never guess Mafia.
I must have misrepresented the rule. The moment that someone calls mafia, the winner is decided. The card flips, and the game ends with whomever won that game. Pick up all the cards from the discard pile, reshuffle, and start over.
The fact that the winner can be decided with each round, piles on a lot of psychological pressure, I believe.
Now WA, I don't want to discard the "3-card deck" idea or whatever you had in mind. I'm sure it would be it's own fulfilling game, but it's not what I had in mind.