Gameforge can learn from Ncsoft's Blade and Soul. They literally removed RNG from weapon uupgrades as they know the western audience isn't gonna stick around long for these type of things. In the Korean version of Blade and Soul you still have to deal with RNG when you upgrade your weapon.
not saying ncsoft is perfect but at this aspect they do really well (altho they do have event bundles which allow whaler to get ahead of other player but hard grinding player can still reach there just much slower) and the other aspect which mentioned before in the forum alrdy is the an currency sales rate in market