its basically impossible for mafia members to get kills on that map using stealth
You can shoot people from below, you can shoot people when nobody is looking, you can shoot someone and quickly hide below, you can make people vote to kill a certain player with the ventriloquist role, you can impersonate a cop by killing him before everyone gets to the roof and hiding the body, you can abduct someone at night, you can have the crazy be under the roof and wait for players to come down to look for bodies, you can shoot someone and say they shot at you or they tossed a body, you can silent-knife someone as the crazy role when nobody is looking, you can ask someone to leave the roof with you to find a body and then kill them on your way down, you can put suspicion on a certain player with different techniques to have them eventually be voted and killed. I can honestly say this is the first time I have heard someone say it's harder for mafia to win compared to the innocents. Most of the time people complain that mafia always win because the innocents can't kill someone for enough reasons (hunches, suspicions, etc.).
games on blok's server are drawn out way too long.
You should not always expect a round to last 5 minutes. Some rounds end before the end of the first night, others take 4 days which is when the dead rise. The length of the round really depends on who the mafia members are and how they play their role or which role they are. Another strategy you can use so the rounds don't seem so long is not dying the first day.
as another idea, there should be more weapon variety than all those 2-shot-kill guns currently available
They are 1-shot kills, and for a good reason. There are 4 different weapon models, although they all function the same way, which is also understandable. I think time was spent more on the game than what the guns looked like.
