Those are both awful for MM. I don't think it's too easy to explain briefly, but basically, MM is kinda expected to take place in the kind of environment where everyone starts out in an obscure location and has to trek to get somewhere open with other innocent. This is extremely important and has developed a lot of strategy and customs. The fact that you can spawn pretty much anywhere in the pyramid except the roof where everyone automatically goes for safety means that you have to climb upwards. This gives the mafia a chance to make the game easier for themselves early on. Also, you can easily do a headcount and figure if someone isn't at the safe zone.
The fact that the majority of the 'working space' is tightly-knit and somewhat mazy means that bodies are difficult to find and easy to hide. The easiest bodies to find are ones that are on the ground, on the roof, or from abductions. Any other murder could take place anywhere in the Pyramid, and you have to look for them or come across them by luck. Which gives the mafia more chances to pluck off innocents. In a city-like map, the majority of the 'working space' is wide open, and the map is moderately large. A single building can't provide a viable safe zone because everyone spawns all over the city. The journey to the safe zone wouldn't go through a common maze-like structure, it would go through pure open space. People gravitate to the streets if they're inno and buildings of they're maf. The game is now about the mafia shooting and staying hidden exclusively, and not about the innocent cleverly determining who the mafia is while the mafia cleverly figure out how to pick off the innocent. I think that's the difference in focus that distinguishes MM from other similar gamemodes. It's more focused on general wit of both teams to slowly whittle each other down, whereas in a game like TTT, the gameplay is built much more around the innocent being sitting ducks while the traitors figure out how to eliminate the innocent without getting discovered.
