you should make more skill events... not one per month, at least 4. you should also burn all the old skills player to player and give 200 gold for each so they can buy the same amount in the store. You did it when you nerf Scorpion so you can do it again. You can put other kind of events, like a defensive one. we should defend some attacks in our finca and be rewarded with some skills, or attacking outposts we can have a 15% of win a skill (a level 1skill) or you can just update the game and we can produce skills, in each attack we have some probability to win a piece, imagine a survival skill piece and when we got 5 of this one we can produce the skill. so many things that the developers can do without only think in players money...if you want to upgrade faster you use money, you buy gold or promotions and ok... you got the things before the other people, but the other players can have those things too even if a player should be more time online and attack all days to win those pieces or something...
another thing that i think is important is that the new players should have the same possibility of having the old sicarios, sicarios that we never see them again in a event or something, like widow or flare, or fiero... those events are gone and what? no one can have them anymore, in the black market never saw a widow and i have 48 contracts out of 75... maybe you can put more slots in the black market, 2 for sicarios, 2 for plata, 2 for material to upgrade sicarios (not the ones that we can win in battles), it will be another way to win some money XD but it will be good for both