Yes, the community already stated this a hundred times, that the blueprint droprate and of course the blueprint roll are a pain in the …
So, we will have to see what happens in the future.
Just an idea, maybe some kind of weapon points. Every weapon/upgrade needs a specific amount of weapon points to build. And you get these points for killing enemys (mooks=1, elites=2, antags=3, bosses=4 and whatnot; values are just an example).