I used the "everything is weightless" mod. Would be a shame if that didn't work anymore. I don't usually mod out difficulty and in Fallout: New Vegas I actually play on hardcore where inventory management is much harder, but for TW2 I just hated the inventory system. The game really encourages you to grab everything you find but then has a very low weight count and no storage.
I was annoyed by that too at first but eventually you realize that there are wwaaayy more ingredients in the world than you'll ever need. I just stopped collecting them at a certain point.