Adding weapons to an RP automatically makes the RP 10 times harder to make successful. If you add guns, people will use them. A good RP would require players to actually work together.
The problem is that this game is full of kids who just want to shoot people no matter what. Whether they have paint, a hammer, or fists, they will attempt to kill you with it, for no reason at all. People will spawn in a city RP and immediately attempt to Flash Mob everyone with a hammer.
Another problem is that 3/4 of the community lacks any type of skill at building. People play blockland, a game where you build stuff, and look for TF2 and call of duty subgames. I bet 1/4 of the players haven't even attempted to build something for the sake of making a nice looking build. Then you get your RP full of generic cube shaped houses, shops, towers, bridges, and so on. When I play on an RP, I actually want to be able to tell what I am looking at. I don't want to be walking down the street and see a building called "shop awsoom" that is 64x64 bricks wide, 5 bricks tall with absolutely no interior detail except some light up buttons that sell you explosives.
In any CityRP, the main goal of half the players is kill. They sell food, work in mines, sell clothes, ultimately so they can get weapons. They don't actually want to be "Hey, I should make a good foodstore to contribute to the city and make it look nice, while getting customers who like the fair priced server I give them", it is more of a "im gona make a food stroe and get money then buy rocket lancher"
Most RPs are stuck in the city theme, and that isn't really what I see becoming great. The city idea has been tried numerous times and it is becoming worn out, and I think it is tiring. I think that a blockland rp should drift away from the city theme and focus on something new. If you want to make a city, you can do it without a mod/minigame and do it without people killing you constantly.