I use to be the same than I realized I can only have one weapon actually in hand at one time with potential 4 mapped. I alway have a rocket launcher mapped even though not big fan for getting second winds. I than narrow down what I like best for other 3 d-pads and what I use most, Than only 1-2 elemental types and one weapon type other what I like.
Same goes for shields. I try them all than get two no more than 3 I like. Store others. Same for grenades and relics pick a couple and stick with them. I generally run 10-12 slot free for loot.