My suggestion or mod idea is for mostly online multiplayer servers with friends, but it is focused around skills like Carpentry, metalworking, mechanics, cooking, farming ect. A mod for a RPG roles aspect i guess.
I would like to see, for example, if you take Mechanic as your starting profession you can reach level 10 in both Mechanics and Metalworking, so you are a Master in that profession, allowing you to fully repair vehicles and such. Whereas everyone else that isn't a mechanic, metalworker, or repairman can get to around level 5 or 6 in mechanics and metalworking allowing them to still do basic stuff but not at 100%. This would make it so if people want stuff fully fixed or built to a higher quality they would go to the master mechanic for help.