Easy fix, allow year one weapons to turn I infusable after you've put two/three etheric light in them. Then they can be infused to 310+ like year two weapons, reason to raid to get the old guns and a reason to get etheric light from POE. Would only work if they brought out a new Type of etheric light though, as I guess people have loads and wouldn't do POE. It's not perfect but better than nothing.