I used to play in an old Roleplay server on SAMP and i will be glad to share some good old experience from SAMP on this server. I suggest to add an army faction, in my opinion this will be a great faction ,realistic and funny. Also, Army can fill a lot of gaps and will be able to make a good roleplay scenes, for exempel Cops can call them for a backup when they need, army can protect the mayor of the city. Like this will be more then LSSD and LSPD and the players will have more choices to join factions and enjoy more roleplaying. You can also add a lot of divisions and ranks exemple
Private > Private First Class > Sergeant > 1st lieutenant > 2nd lieutenant > Captain > Colonel >General.
Air devision for the planes.
ground devision for the tanks and the ground units.
sea devision and this includes the boats.
Ps: Players can join divisions from the third rank.